Chapter 4 — The Cable Splicer Beneath the Sea

Air Compression Chamber

At eight o'clock in the morning, the saturated dive chamber located on the lower level of the Wanli was bright under neon lights, the air thick with the smell of rubber and cold metal. Sơn sat on a steel chair, letting Chu Tuệ Lam stick each piece of heart-monitoring electrode on his chest, while Bách stood next to him, already wearing the top half of his pressure diving suit, only missing his helmet.

"Heart rate seventy-two, blood pressure one hundred twenty over eighty." Lam read the data from the monitor and nodded with satisfaction. "Stable as always."

"Since when are you worried that I'm unstable?" Sơn asked, his voice had a rare hint of joking.

"Since I learned clearly about what happened at Đá Dựng three years ago," Lam replied straight, without beating around the bush, still looking at the meter. "I'm not the one to judge your decision at that time. I'm just the person responsible for making sure you don't bring a wrong decision from the past to the bottom of the sea this time."

Those words made Bách pause for a second while he was fastening the chest strap. He didn't say anything, just glanced at Sơn and then turned away, pretending to be busy with the lock.

"I know," Sơn replied, his voice lowered but he did not avoid it. "Just keep a close eye on it. If you see anything unusual, stop diving immediately, no need to ask anyone else's opinion."

"That's my right, I don't need your permission." Lam removed the last electrode piece and closed the lid of the tool box. "But thanks for saying it."

In the corner of the room, Minh Thư stood in front of the communications control panel, wearing headphones, checking each communication channel that would connect with the two divers throughout the shift. This was the first time she sat in this position for real, not in a simulated training session.

"Main channel, backup channel, emergency channel, all clear." She reported, trying to keep her tone professional even though her heart was beating faster than usual. "The umbilical cord pressure is stable, the cameras mounted on both of their helmets transmit good images."

"Remember the most important rule." Sơn told her, while the technician in charge of the compression chamber began to attach the diving helmet to his head. "If you hear anything unusual in our voices down there, even if it's just a longer silence than usual, immediately notify Ms. Lam and Mr. Bách on the water's edge. Don't wait to be sure first. Under water, a second of hesitation can be the difference between fixable and unfixable."

"I remember." Thư nodded and wrote that sentence down on a piece of paper stuck next to the dashboard, as a reminder to never forget.

Outside the compression chamber, through a small glass window, Hòa stood watching with Trung, who had just landed a small helicopter on the temporary landing pad on the deck half an hour ago, without warning, just calling to say "I need to be there in person" before hanging up.

"How long will it take the compression chamber to take them to a depth of eighty-five meters?" Trung asked, trying to keep his distance from the devices whose uses he didn't fully understand.

"About forty-five minutes, slowly increasing the pressure to let their bodies adjust," Hòa answered, his eyes not leaving the glass window. "Then the diving bell will take them out, directly connected to the marine environment at that exact pressure. They will live in this pressure continuously until the job is done, not returning to surface pressure until the final decompression shift."

"So that means the whole time, no matter what happens on the water, they have to stay at that pressure?"

"That's right. There's no way to get them up quickly without risking death." Hòa turned to look straight at Trung. "That's why I always emphasize, every decision before the chamber closes is more important than any decision after. Once the door closes, we don't have many options left."

Trung remained silent, looking through the glass window inside, where Sơn had finished putting on his diving helmet. Only his face appeared behind the glass screen, his eyes so calm that it was unbelievable for a person about to enter a space where the smallest mistake could never be corrected.

"Is he always like that before every diving shift?" Trung asked softly, almost asking himself.

"Are not," Hòa replied. "He wasn't that calm before. Before he was excited, almost impatient. After the accident, he learned to be calm, but it was a different calm, built from scratch, not something that was already there."

Before entering the compression chamber, Sơn stopped for a moment at the door, looking towards the communication control panel where Thư was sitting. "Do me a favor and check again," he said. "The maximum bottom time chart for a depth of eighty-five meters is how many minutes before emergency decompression is required?"

Thư quickly flipped through the notebook and followed the data table that she had memorized before but had never had to apply in practice. "One hundred and twenty minutes in standard mode, sir."

"Correct." Sơn nodded. "I'm not asking because I don't remember, but because I want to make sure there are at least two people on this ship who know that number by heart, not just me. If anything happens to me down there, people on the water can't wait for me to repeat it."

The words made Thư pause for a moment, realizing that this was not simply a knowledge test. That's part of the invisible process that Sơn has built for himself over the past three years — not trusting anything that only exists in one person's head.

"I got it," she replied, her voice much more certain than it had been a few hours ago.

The technician operating the compression chamber began reading the final checklist through the internal speaker, in a monotone voice, almost chanting: breathing air pressure, helium-oxygen ratio in the heliox mixture, chamber temperature, humidity, CO2 filtration system status. Each entry was confirmed with a brief "clear" from both Sơn and Bách; neither one missed a single entry, even though they had repeated this process hundreds of times in their careers.

Outside the glass window, Trung observed the entire process with the expression of someone witnessing for the first time the almost ritualistic meticulousness of deep diving. He is used to meetings where decisions are made in a few minutes, and Excel tables that can be edited immediately when there are errors. Here, everything was uncomfortably slow, but each slow second carried a weight that he began to feel, even though he didn't fully understand.

"I'm sorry for rushing you guys earlier," Trung said to Hòa, still looking through the glass window. "I don't mean to take this process lightly. I'm just used to a different kind of countdown clock."

"I know," Hòa replied, his voice less tense than last night's video call. "We're both counting down to something. It's just that your watch counts by the number of people lost connection, and mine counts by the number of minutes a person can withstand pressure under eighty-five meters of sea water. Neither is more important than the other, it's just that we need to learn to look at both clocks at the same time."

In the compression chamber, the circular steel door began to close with a characteristic compressed air hiss. Sơn looked at Bách through the glass of his diving helmet, the two exchanged a short nod, no further words were needed. It was a private language between people who had faced the same pressure of the deep sea, where superfluous words only slow down the already precious rhythm of breathing.

"Initiate pressurization." The technician operating the compression chamber announced over the intercom, his hand on the control lever.

The sound of compressed air hissing became stronger. The barometer on the wall began to inch forward, the numbers rising slowly but surely, step by step, bringing the two men in the steel chamber closer to the kind of pressure that the human body was never built to withstand, but still learned to survive within, as long as every step was in order, not a single step was skipped.

Minh Thư sat in front of the communications control panel, headphones placed close to both sides of her head, listening to the steady breathing of Sơn and Bách echoing through the main channel, two slow, parallel sounds, like two watches carefully wound to run at the same rhythm throughout the coming hours.

She glanced at the piece of paper stuck next to the control panel, the words she had just hastily scribbled: one hundred and twenty minutes, not waiting for certainty. Outside, the wind began to whistle louder through the deck door, a small sign that while the two people in the compression chamber were slowly adjusting to the pressure, what was waiting for them on the sea surface above had no intention of slowing down at all.

On the barometer, the number continues to move up step by step, steadily, it cannot be accelerated, it cannot be delayed, it can only wait. Thư lightly tapped her fingers on the table to the rhythm of that number, trying to turn her impatience into a form of disciplined patience, just like what she had just learned in the few short hours since setting foot on this ship.