svetikya Chapter 16 Thermos Cup
Chapter 16 Thermos Cup
The sound inside the pipes is different from the sound outside.
The sounds outside are scattered, directional, and attenuated; they are blocked by buildings and carried away by the wind. The sounds inside the pipes are dense; they are reflected and superimposed by the concrete walls, forming a continuous low-frequency pressure in Xie Chengzhou's ear canal—the sound of water, his own footsteps, and Lao Zhao's footsteps following behind him, all mixed together, as if the space is constantly breathing.
He walked about fifty meters.
He listened intently as he walked, constantly scanning the pipe walls on both sides with the beam of his flashlight. The concrete lining was uniform, with construction joints spaced approximately every two meters—a standard segmented construction method, which he recognized. The water depth and flow velocity remained stable.
Then he discovered the first protrusion on the left side of the wall.
It wasn't obvious. If he hadn't been consciously sweeping the wall, he would have walked over. The protrusion was about three millimeters higher than the pipe wall, oval in shape, about five centimeters in diameter, and its surface color matched the surrounding concrete, but the texture was different—the surrounding concrete was rough, while the protrusion was smooth, like a metal piece embedded in the concrete, its surface covered with concrete slurry, but over the years the covering had peeled off, revealing what was underneath.
Xie Chengzhou stopped, did not approach, and stared at it for ten seconds.
He felt a slight chill on the back of his neck.
It wasn't very strong, but he recognized the feeling—he had the same feeling in #001, a second before discovering the hidden rule C (amplified sound in the chemical area). He recorded this perception in his memo, labeling it "Sense of Stress Concentration - Precursor," pending verification.
Now it has reappeared.
In his memo, he noted: "Wall protrusion, left side, approximately 50 meters from the entrance. Shape: elliptical, 5cm in diameter, smooth, embedded, non-structural. Stress concentration sensation: triggered. Judgment: not randomly distributed, possibly a functional component. Do not touch, pending evaluation."
He switched the flashlight to his left hand and lightly brushed his right hand against the side of his trouser leg—his hand was no more than thirty centimeters away from the protrusion at its closest point. He didn't touch it; he withdrew his hand and continued walking.
"Stop for a moment," Old Zhao said from behind him.
Xie Chengzhou stopped and turned around.
Old Zhao didn't move forward. He stood next to the protrusion, holding his thermos, his eyes fixed on the wall. His gaze wasn't on the protrusion itself, but on the pipe wall next to it—about twenty centimeters to the left of the protrusion, there was a very thin water stain that stretched from the top of the wall to the water surface, a mark left by water flowing along the wall over a long period of time.
"This water stain," Old Zhao said, "isn't right."
Xie Chengzhou walked back, squatted down, and held the beam of his flashlight close to the water stain.
Old Zhao is right. Water stains on the pipe wall should be evenly distributed; wherever there are cracks or construction joints, there will be seepage, and the location of the water stains should follow a pattern. But this water stain isn't on the construction joint; it's in the middle of the joint, next to that protrusion.
The water stains didn't come from seepage, but from that bump.
Xie Chengzhou added a line to the memo: "Protrusion, water stain association, slight water marks on the protrusion surface, judgment: there is a hydraulic mechanism or sealed cavity inside, with long-term minor leakage. Functional component confirmed. Touch risk: unknown, but the intensity of stress concentration suggests a high risk."
He stood up. "Old Zhao," he said, "don't touch this."
Old Zhao nodded. "I know," he said. "I've been a plumber for thirty years, and I've seen this kind of thing before. It's called a pressure sensor, and it's installed in pipes to monitor flow." He paused for a moment. "I'm not sure what will happen if I touch it, but it certainly won't be a good thing."
Xie Chengzhou paused for a moment on the "pressure sensor".
The established rule states that fluid anomalies are triggered by a sudden increase in flow rate, and the system must reach the maintenance room within 60 seconds. If this protrusion is a pressure sensor, and touching it would trigger an increase in flow rate—
He glanced back in the direction they had come from.
They were about fifty meters from the entrance maintenance room. The water in the pipes was twenty centimeters deep and flowing slowly; a normal walking speed was about fifty meters per minute. Fifty meters—they could run back in a minute—but there couldn't be any accidents.
In his memo, he wrote: "DB #002 Hidden Rule Assumption A: Wall protrusion = pressure sensor, touching it triggers fluid anomaly. Verification method: Observe the distribution pattern of protrusions in the subsequent pipes. If the distribution is regular, the assumption is valid. Current action: Mark all protrusion locations and absolutely do not touch them."
He raised the flashlight again and continued walking.
When they reached the 80-meter mark, Xie Chengzhou turned off the flashlight.
It wasn't an accident; he turned it off on his own.
He had already written down the plan in his memo: "Priority verification: Will the light source reveal the location? Method: Briefly turn off the light source at a safe distance and observe whether it triggers a reaction." Now he was executing the plan.
Darkness came immediately.
It wasn't gradual; it was abrupt. The flashlights were switched off, extinguishing the light in the pipes, leaving only a faint, orange-yellow glow from the emergency light in the maintenance room far behind them, so blurred it was almost unrecognizable. Xie Chengzhou stood in the darkness, motionless, switching all his senses to hearing.
The sound of water. His own breathing. Old Zhao was behind him, his breathing steady, without any panic.
Then came the third sound.
It's not just one, it's many.
They appeared almost simultaneously, as if a switch had been flipped, and suddenly there was a dense, rapid sound of splashing water in the darkness—not just one thing moving, but many things moving, and very fast, so fast that he didn't have time to do any calculations and could only rely on instinct to judge: ahead, many things were approaching.
Xie Chengzhou didn't move in the darkness, but his hand was already gripping the flashlight switch.
He didn't press it.
He had dealt with many emergencies on construction sites, and he knew that revealing his location before understanding the nature of the threat was not a good option. He focused all his senses on his hearing, going over the direction, distance, and density of those sounds—ahead, about fifteen to twenty meters away, the number was uncertain, many, their sounds of movement overlapping each other, with very small intervals between them, like a group of things moving densely in water, each individual small, but the combined sound had a kind of oppressive feeling that sent chills down his spine.
A sense of stress concentration.
It wasn't mild, it was very strong, stronger than when he discovered any hidden rules in #001.
He brought his mouth close to Old Zhao's ear and whispered, "Don't move, don't make a sound."
Old Zhao didn't speak. But Xie Chengzhou heard a very faint sound—Old Zhao tightened the lid of the thermos. A slight scraping sound of metal threads, less than a second, followed by complete silence.
Xie Chengzhou knew what Lao Zhao was thinking: the thermos was metal, and it would make a sound when it hit the pipe wall. He made the right judgment in the shortest amount of time.
Those sounds are still getting closer.
It's even faster now.
In the darkness, Xie Chengzhou pulled the backup light source from his pocket, holding it in his left hand and the main flashlight in his right, his index finger resting on the switch. He mentally reviewed the two options: turn on the light, see clearly what they were, and expose his position; don't turn on the light, remain hidden, but be completely unaware of any threat.
He chose to turn on the light.
The light came instantly.
He saw them.
The pipes were densely packed with them.
Their bodies were flat, with short, powerful limbs and dark gray, moist, and glossy skin. They resembled the shape of a giant salamander, but were smaller, each about thirty centimeters long and fifteen centimeters wide. They moved swiftly close to the water's surface, their limbs paddling rapidly, creating dense, fine splashes—the very sounds he had heard in the darkness. They had no eyes, or rather, he couldn't see any eyes. Their heads were blunt and rounded, but their mouths were open—and inside were teeth, not in a row, but densely packed, fine teeth that curved inwards, like a structure specifically designed to grip prey and prevent escape, rather than to tear it apart.
They all stopped the moment he turned on the flashlight.
one second.
Just one second.
Then they all turned towards the light source.
It wasn't a slow turn; it was simultaneous, as if they had received the same signal. All their heads turned towards the beam of the flashlight at the same time, and then they started rushing over, more than twice as fast as before. The sound of splashing water became a dense, almost continuous noise, like rain hitting the surface of water, but coming from the front towards him.
Fifteen meters.
Xie Chengzhou did not wait for them to arrive.
He turned on the spare flashlight and threw it deep into the pipe ahead, while turning off the main flashlight.
Darkness has returned.
He pressed his back against the left side of the pipe wall, pulled Old Zhao over, and whispered, "Stick against the wall, don't move, don't make a sound."
He felt Lao Zhao's back press against the concrete wall next to him.
Then he heard the sound of the spare flashlight falling into the water—plop. The beam of light hit the surface of the water and began to drift forward with the current, drifting deeper into the pipe, drifting into the darkness.
The sounds paused in the darkness for less than a second.
Then they all turned around.
Xie Chengzhou pressed himself against the wall in complete darkness, listening to the dense splashing of water passing in front of him, to his side, and past his feet—at its closest, he estimated, they were no more than half a meter away. He could feel the water ripple slightly at his ankles due to their rapid movement, as if something had brushed past his feet but hadn't touched him.
He didn't move.
He even suppressed his breathing, controlling his breath in his chest cavity so that it wouldn't turn into a sound.
The sounds went on, getting farther and farther away, getting fainter and fainter, until they disappeared deep into the pipe, behind the drifting light source.
But at the last moment, one was a step too slow.
Xie Chengzhou felt it—a cold, wet, sticky sensation brushing against the outside of his right calf for less than a second, like a reptile glancing sideways at his leg as it turned. His skin wasn't broken, but the sensation lingered, cold, fishy, carrying the stench of stagnant water he'd seen in construction site flooded areas, but stronger, more direct. He didn't move; he suppressed the feeling and continued to wait.
Xie Chengzhou waited in place for about twenty seconds without moving.
For twenty seconds, the only sound in the pipe was the sound of water.
He turned the main flashlight back on, shining the beam forward, backward, and left and right.
No more.
His breathing regained its steady rhythm, emerging from his chest. He glanced down at his hands; they were steady.
Old Zhao stood beside him, still holding his thermos, the lid screwed on tightly, without uttering a sound. There was no fear on his face, only the expression of "this situation was terrible, but it's over," the same expression Xie Chengzhou had seen on many veteran workers at the construction site after the danger had passed.
Xie Chengzhou noted in his memo: "#002 Threat Entity: Crawler: Confirmed. Appearance: Salamander-shaped, dark gray, limbs, dense teeth, no visible eyes, body length approximately 30cm. Quantity: Large, operates in groups. Speed: Extremely fast, when sprinting as a group, its speed far exceeds that of an individual. Perception mechanism: Follows light sources, not sound, not heat. Pauses for about 1 second after the lights are turned off, then turns towards a new light source."
He paused after this record and added a line: "The backup light source has been used as bait. The drifting strategy is effective, but the execution window is extremely short—from turning on the light to throwing out the backup light source, it takes no more than two seconds; any slower and they'll be there. Backup light source consumed: 1. Remaining: 0. No backup bait will be available when encountering groups of reptiles in the future."
He gripped the flashlight tightly and continued walking.
Old Zhao walked beside him for about five minutes without saying a word.
Xie Chengzhou noticed that he kept looking at the pipe wall, not casually, but purposefully. His gaze would linger on certain spots for a second or two before moving on. Xie Chengzhou followed his gaze several times but didn't find anything special. However, he didn't interrupt Lao Zhao. He knew what this "experienced person looking at something they were familiar with" meant—let him look, and wait for him to speak.
At the 120-meter mark, Lao Zhao stopped, placed his hand on the pipe wall, closed his eyes, and listened for about ten seconds.
"There's a fork in the road ahead," he said.
Xie Chengzhou shone the flashlight forward. The pipe was straight in his line of sight, without any branches. "How did you know?" he said.
"Listen," Old Zhao said, "the sound of water."
Xie Chengzhou placed his hand on the wall, closed his eyes, and listened.
The sound of water, the echo, the low-frequency resonance unique to pipes. Then he heard—beneath that uniform sound of water, there was a slight frequency difference, like the sounds of two streams of water superimposed, but not perfectly synchronized, with a very small phase difference, originating about thirty to fifty meters ahead, and then propagating backward in the pipe, superimposing into the sound of water he heard.
Two streams of water. In two directions.
"Forking," Xie Chengzhou said.
Old Zhao opened his eyes. "Yes," he said, "about thirty meters ahead, the water flows in from two directions, which means the pipe branches there, or there's a branch pipe connecting to it." He paused. "Is it on your map?"
Xie Chengzhou opened the memo and reviewed Rule 2 again: "End condition of the journey: Reach the main control room at the end of the pipeline and close the flow control valve." There was no map, no route instructions, nothing at all.
"No," he said.
Old Zhao switched the thermos cup from one hand to the other. "That's troublesome," he said, his tone calm, as if to say, "I've encountered this situation before. It's difficult to handle, but I can manage it." "If you choose the wrong direction in a branching pipe, you might end up in a dead end or a branch pipe with no exit."
Xie Chengzhou noted in his memo: "#002·Fork in the road·Approximately 30 meters from current location·Route not specified in the rules·Old Zhao: The fork was determined by the sound of the water. Method for determining the direction of the fork: To be confirmed."
Then he gripped the flashlight tightly and walked forward.
He needs to figure out how to determine which direction is correct before reaching the fork in the road.
He was thinking about this as he walked, his feet moving forward step by step in the water, each step consuming the distance between him and the fork in the river.
The control room is at the end. The end of the pipeline means the point where the flow rate is highest—all the water from the branch pipes eventually flows into the main trunk, which leads to the control room. He should choose the pipe with the highest flow rate because water flows downhill, towards the main trunk, and towards the control room.
He went over this deduction in his mind and then wrote it down in his memo: "Bifurcation judgment principle: Choose the direction with greater water flow, because the direction of water flow convergence = the direction of the main pipeline = the direction of the main control room. Verification method: Compare the water flow velocities on both sides at the bifurcation point."
Then his flashlight beam fell on the wall in front of him, and he saw a second protrusion.
This bump is different from the first one.
The first one is oval, embedded, with smooth edges. This one is irregular, as if someone used a tool to carve a small hole in the concrete wall, put something in it, and then filled it with concrete, but the filling was not done well, with a slight bulge on the surface and uneven edges.
Xie Chengzhou paused on the protrusion for three seconds.
No sense of stress concentration was observed.
He recorded this information: "Wall protrusion, second location, approximately 115 meters from the entrance, shape: irregular, obvious repair marks, not embedded. Stress concentration sensation: not triggered. Judgment: possibly a non-functional component, or its function differs from the first location."
He went around it and continued walking forward.
The fork is twenty meters ahead.
He could see it; when the beam of the flashlight shone there, the pipe split into two. The pipe openings on the left and right sides had the same diameter, both two and a half meters, and water was flowing out from both, both of which were black.
Xie Chengzhou stood before the fork in the river and surveyed the water on both sides.
On the left side of the water, the current was about four centimeters per second. He splashed his foot in the water, and the ripples spread as fast as he estimated. On the right side of the water, he splashed his foot, and the ripples spread even faster, about six centimeters per second.
The water flow is faster on the right. A faster flow means a larger volume, which means it's on the main channel.
He took a step toward the right-hand opening of the pipe.
Then Lao Zhao grabbed his arm.
"Wait," Old Zhao said.
Xie Chengzhou stopped. "What?" he said.
Old Zhao didn't say anything. He placed the thermos on the water's surface, let it float for a moment, and observed the direction it was drifting. The thermos paused briefly at the confluence of the water streams on both sides, then veered to the left.
It veered to the left.
Xie Chengzhou paused for two seconds on this detail, "The water flowed to the left," he said.
"Yes," Old Zhao said, "the water flows faster on the right because there's a drop in the pipe on the right, so the water flows downwards and the flow rate is faster, but it's not necessarily the main pipe, it could be a drainage branch pipe." He picked up the thermos from the water and tightened the lid, "The water in the main pipe flows forward, not downwards, so the flow rate may not be the fastest, but the direction is correct."
Xie Chengzhou crossed out the judgment principle he had just written in his memo and rewrote it: "Bifurcation judgment principle revised: Fast flow velocity ≠ main channel, water flow direction needs to be determined (horizontal = main channel, vertical drop = branch pipe/drainage pipe). Lao Zhao's judgment method: use floating objects to test water flow direction. Effective."
He took a step toward the left-hand pipe opening. "Old Zhao," he said, "let's go."
Old Zhao gripped the thermos cup again and followed.
They entered the left-hand pipe, and Xie Chengzhou shone the beam of his flashlight forward.
The pipe continued to extend forward, dark and deep, with the sound of water echoing around them.
As Xie Chengzhou walked, he reviewed the day's information in his mind: crawlers chase light, sensors must not be touched, and forks in the water flow must be determined by the direction of the water flow, not the speed. These three pieces of information, these three rules, were all acquired while he was walking; none of them were known beforehand.
He wrote these things down in his memo, then closed it and moved on.
The darkness ahead has no end.
The flashlight beam shone for twenty meters, and beyond that, it was still dark. He knew there were crawlers in the darkness, possibly more than one. His backup light source was used up, and he only had this one flashlight left. If this flashlight malfunctioned—
He didn't continue to think about this hypothesis.
He gripped the flashlight tightly and walked forward.
Then he felt it.
A slight pressure change was felt beneath his feet, through the soles of his shoes and through the water. It wasn't a vibration, but pressure, like a slight increase in water volume upstream, the pressure wave arriving before it reached him.
He stopped, placed his hand on the pipe wall, and felt the pressure.
It is strengthening.
He glanced down at the water's surface. The water flow hadn't changed, but he could feel the water pressure rising slightly, as if a valve upstream of a pipe was slowly opening—not fully open yet, but already begun.
In his memo, he wrote: "Water pressure change - slight increase - felt underfoot - water flow velocity has not changed yet. DB #002 - Implicit Rule D Assumption: There is a pre-compression phenomenon before the fluid anomaly is triggered - the flow velocity first decreases briefly and then increases sharply. Current state: pre-compression stage? Time window: unknown."
He closed the memo and glanced back at Old Zhao.
Old Zhao also sensed it. His feet were in the water, and the expression on his face wasn't one of fear, but rather one of "I know this is a bad situation."
"Water pressure," Old Zhao said.
"Yes," Xie Chengzhou said.
The two looked at each other for a second.
Xie Chengzhou mentally calculated the distance: they had walked about 170 meters, and the nearest maintenance room was the one at the entrance, also 170 meters away. At a normal walking pace of 50 meters per minute, it would take about three and a half minutes. However, Rule 1 stated that the 60-second window would only be triggered when the flow suddenly increased, and it hadn't been triggered yet, so there was still time.
He didn't know how much time he had left.
"Keep going," he said, "hurry up."
They quickened their pace, the sound of splashing water echoing in the pipes, louder and faster than before.
Xie Chengzhou gripped the flashlight tightly, walked forward, towards the next maintenance room, towards the main control room he hadn't yet reached.
The water pressure continued to rise beneath his feet, slightly but steadily, like a timer counting down in a place he couldn't see.