stonecrandall Chapter 21 Calculation
Chapter 21 Calculation
The third maintenance room is located at 640 meters.
When Xie Chengzhou entered, he first scanned the room, which was basically the same as the second maintenance room: circular, five meters in diameter, with emergency lights, supply boxes, and water. He walked to the supply box, opened the latch, and pulled open the door.
There's something inside.
A spare flashlight, with a black metal casing, smaller than the one he was holding, was a single-battery model with low light intensity but long battery life. Next to it was a roll of emergency rope, red, about ten meters long, thin, and capable of supporting about one hundred kilograms.
He took out the flashlight and the rope, turned on the flashlight to make sure it was working, then turned it off and put it in his coat pocket. He coiled the rope and hung it on his belt.
"This supply crate is intact," he said. "The second one was taken, but this one isn't."
Old Zhao walked over, glanced at it, and said, "That means that person didn't get here," he added, "or something went wrong when they got here."
谢承洲在备忘录里记：「第三检修室·补给箱·完整·备用手电筒×1+应急绳索×1·已取用。推断：JG-0471或其他玩家未到达第三检修室，失蹤位置在550-640米之间。」
Then he found a spot indoors near the pipe opening, sat down, placed the flashlight on his knees, closed his eyes, and began to listen.
He listened for three minutes.
The periodic undulating sound was clearer in the maintenance room than in the pipes. Old Zhao was right; the acoustics in the maintenance room were better, with less reflection and cleaner sound. He remeasured the frequency of the undulating sound: the single opening and closing cycle was about 3.2 seconds, slightly shorter than the 3.5 seconds he measured in the pipes. The error might be due to background noise interference from the pipes.
He waited, waiting for an increase in traffic.
After waiting for about four minutes, the pitch suddenly changed.
It's not that it gets louder, it gets denser—the frequency of the fluctuations increases, from once every 3.2 seconds to once every 1.5 seconds, and then the sound of the water begins to increase evenly, like adjusting the volume, rising from the "normal" of the basic water sound to "higher", and then continuing to rise.
He started timing in his head.
The sound of the water rose from normal to the upper limit of his perception within about fifteen seconds—that is, the sound intensity of the water that he judged "the fluid anomaly was about to be triggered." It then maintained this intensity for about twenty seconds before starting to fall back, taking about twenty seconds to return to normal levels.
A complete surge in traffic lasts approximately 15 seconds, peaks for about 20 seconds, and declines for about 20 seconds, for a total of about 55 seconds.
Then he continued to wait, waiting for the next time.
Old Zhao sat next to him, his thermos cup on his lap, listening without saying a word.
Approximately eleven minutes later, the second surge in flow began.
Xie Chengzhou redid the timing: the ascent lasted about eighteen seconds, the peak lasted about twenty-two seconds, the descent lasted about twenty seconds, for a total of about sixty seconds.
The interval between the two events: approximately eleven minutes.
他睁开眼睛，把备忘录打开，开始写：「流体异常周期·实测（第三检修室）：①单次开合周期：约3.2秒。②完整流量增大事件：上升15-18秒+高峰20-22秒+下降20秒≈55-60秒。③两次事件间隔：约11分钟。」
He then compared this number with the explicit rules: "After a fluid anomaly is triggered, the player must reach the nearest maintenance room within 60 seconds."
Sixty seconds is the window of opportunity, and eleven minutes is the cycle.
They were about 160 meters from the third maintenance room to the main control room. At Lao Zhao's walking speed of 41 meters per minute, it would take about four minutes.
Four minutes is far less than eleven minutes.
They can travel the remaining distance within a complete cycle interval, and as long as they depart before the next fluid anomaly trigger and arrive at the control room before the next trigger, they will not be caught by the fluid anomaly.
"Old Zhao," he said, "we have an eleven-minute window, and it will take four minutes to walk the remaining 160 meters." He handed the memo to Old Zhao, "Please check if my calculations are correct."
Old Zhao took the memo, shone his flashlight on it, looked it over, and then handed it back. "The numbers are fine," he said, "but you're using my pace." He paused for a moment, "You'll be faster if you walk yourself."
"I know," Xie Chengzhou said, "using your pace, you'll have more leeway."
Old Zhao thought about what he said for a moment, then nodded and said, "Okay."
谢承洲在备忘录里把出发时机的计算写完整：「出发时机：下一次流体异常触发后立即出发（此时距离下下次触发约11分钟）→4分钟内到达主控室→关闭阀门→历境结束。风险：若路线上有传感器或爬行者，实际行进时间可能超过4分钟，需要留出缓冲。缓冲量：11-4=7分钟，缓冲充足。」
He then included another option: "Alternative: Do not move during the peak of the abnormal fluid flow, wait for the water level to drop before setting off, and use the 11-minute window after the peak to complete the journey. Advantages: Avoid traveling when the water level is at its highest. Disadvantages: Waste about 1 minute of waiting time, but the window is still sufficient."
He compared the two options. "The second one," he said, "is to wait until the fluid anomaly has passed and the water level has dropped before proceeding. It will be safer to travel after that."
Old Zhao glanced at him. "You have to wait until the water level is at its highest," he said, "and then wait for it to recede before you leave."
"Yes," Xie Chengzhou said.
Old Zhao unscrewed the thermos, took a sip, and said, "Then we'll wait now."
Xie Chengzhou calculated the waiting time in his memo: the second fluid anomaly had just ended, and the next one would occur in about eleven minutes. They would need to wait about eleven minutes before the fluid anomaly was triggered again, lasting about sixty seconds, and then they would set off.
Total waiting time: Approximately twelve minutes.
He wrote in his memo: "Waiting plan: Current time T=0, next fluid anomaly will be triggered at T≈11min, peak will end at T≈12min, depart at T=12min, arrive at the main control room at T≈16min, close the valve, end the experience."
Then he closed the memo, leaned against the wall of the maintenance room, and waited.
Old Zhao was next to him, holding a thermos cup with the lid screwed on, his eyes fixed on the pipe opening, waiting.
The maintenance room was quiet, with only the sound of water and that periodic, fluctuating sound, once every 3.2 seconds, even, like something breathing rhythmically.
Xie Chengzhou used those twelve minutes in his mind: he sorted out all the information from when he entered the pipeline until now, categorized the verified, unverified, and excluded information, updated the roadmap to the latest status, and summarized all the information provided by Lao Zhao into the corresponding knowledge categories.
Then he wrote a line in his memo, a line he had gone over in his mind three times before writing it down: "Old Zhao's knowledge covered my blind spots. If I had entered this instance alone, I wouldn't have heard the flow control valve, wouldn't have discovered the supplementary section, wouldn't have been able to determine the direction of the fork, I would have moved much slower, and the risks would have been much higher."
He paused below that line, then added: "The value of a variable lies not in how fast it can run, but in what it knows."
He closed his eyes and waited.
About eleven minutes later, the undulating sounds began to become more frequent, and the sound of water began to increase.
He opened his eyes. "Here I am," he said.
Old Zhao gripped the thermos tightly. "Okay," he said.
They waited for the sound of the water to reach its peak, waited for it to maintain, waited for it to begin to fall back, and waited for it to return to normal levels.
Xie Chengzhou wrote the last line in his memo: "T=12min, depart."
Then he stood up, gripped the flashlight tightly, checked the spare flashlight in his pocket, and checked the emergency rope on his belt. "Let's go," he said.
Old Zhao stood up and followed.
They came out of the third maintenance room, entered the pipeline, and headed towards the main control room.