Four o’clock in the electrical record meant yesterday.
Seorin checked October 26 on the sheet and dated her own note. She had turned so many pages since morning that yesterday and today had nearly slipped into one box.
ISOLATE LIGHTING. CHECK SURVEILLANCE POWER SEPARATELY.
Doun read the words silently. Outside the office window, daylight shone. On the monitor, the connecting passage still depended on lamps. Half a level down without a window, even day had to be switched on by someone.
“Power consumption alone won’t tell us who changed a camera,” he said.
“What can it tell us?”
“What went off, and when. Whether everything went down, or just the lights.”
She moved the cabinet photograph to a separate screen. The device’s TODAY, 17:56 appeared inside a photograph taken yesterday. Yesterday’s today. She first replaced that word with a date.
DEVICE DISPLAY: OCTOBER 26, 17:56. OFFSET FROM STANDARD TIME UNCONFIRMED.
Beside it, she placed 16:00 from the electrical job sheet. Lining up two numbers made it feel as though she knew the whole sequence. She moved the papers apart. They did not yet share a clock.
Eungyeong asked the employee who had delivered the material to contact its author. The electrical worker was on another site and explained by video call first. Seorin touched no electrical controls. Switching this building off and on now would not bring back what someone had done yesterday.
The worker said he had checked the recorded times against his phone. The lighting circuit had been temporarily isolated to inspect a leak in the connecting section. The notified area was Block 3, Lower Auxiliary. The office monitor and the relay cabinet’s auxiliary power were separate.
“Did the picture stay on?”
“I didn’t check the monitor. I was working on the lighting.”
That answer helped. Someone needed to leave an unknown section for another person to check.
After the call, she marked the electrical record and the worker’s explanation in different colors. The paper recorded a job; the voice was its author’s present account. She separated what matched from what remained empty.
Doun traced the layout’s lines.
“Keeping the relay powered while isolating only the lighting area is possible. We still need to check where each camera gets its power.”
“Both the camera at the old Room 214 location and the connecting-section camera.”
“Yes. We can’t count them as one again because they share a label.”
She looked at the handwritten note beneath the monitor. CONNECTING SERVICE PASSAGE remained where she had put it yesterday. There was little room below. Better to get more paper than shorten the necessary explanation.
A preserved set of photographs arrived from the site staff. Progress pictures the clearance contractor had posted to the work chat yesterday afternoon. Not every original capture time was confirmed. Server receipt times and the files’ sources had been preserved separately.
The first showed a dim monitor.
CHANNEL 4. OUTSIDE ROOM 214.
Ignoring the label, she enlarged the door’s base. Three grooves crossed the metal threshold. Like the empty Room 214 she had inspected yesterday.
“This could actually be that room.”
“Can the threshold alone confirm it?” Doun asked.
She reduced the magnification. A dented corner on the fire-hose cabinet to the left; a small circular mark on the door. Their positions matched yesterday’s site photographs. She marked three corresponding features.
“At least it isn’t the blue connecting-section door. Three features match our photographs of 214.”
He nodded. Having her own question returned was uncomfortable and necessary.
The next photograph showed another door under the same Channel 4 label.
Silver grille. Black rubber strip. Smooth threshold.
Her hand stopped above the screen.
She had thought only of a label wrong from the beginning. But if it had been right until a certain point, and the place behind it had changed, that was different. Perhaps someone had changed the incoming picture, rather than simply neglected a paper label.
“The filming location changed between them.”
“We don’t yet know whether the camera moved or its input line changed,” Doun said.
She rewrote the sentence.
LOCATION SHOWN ON CHANNEL 4 CHANGED.
A small difference, enough to remove an assumption that someone must have gone to the roof. The input might have changed at the office, or routing at the relay cabinet. Two photographs could not identify the path.
The first reached the work chat at 15:58. The second, 16:08. Both included monitor timestamps. With the device clock’s error and delay status unknown, neither displayed value could be used directly as real time.
They reached the worker who had sent them.
He said he had been asked to check his picture and sent each photograph straight from the site. The first was before isolation; the second after lighting was restored. He had not remained in the office for all ten minutes between them.
“Were they taken when you sent them?”
“Almost immediately. I couldn’t tell you to the second.”
Seorin kept almost. There was an account of little time between capture and transmission, not accuracy to the second.
The electrical job sheet said isolation at 16:00, restoration at 16:06.
That interval fell between the two photographs showing different places.
“Can we say it was changed then?” Eungyeong asked.
“We can narrow the range. Isolation itself doesn’t mean a cable was switched.”
“It might have been a mistake during site work.”
“We’ll check that possibility too.”
Seorin kept mistake at the same distance as intention. Neither should become a reason to inspect less material.
Wind shook the office door once, after someone closed the fire door at the corridor’s end. She turned to the monitor. On Channel 1, the access worker moved now. On Channel 4, a worker who had passed a little earlier appeared at last.
Present and past turned their heads within one screen.
“Check people this way and you could count someone already gone as still here. Or the reverse.”
Yunjae heard her as he came in.
“That’s why records checking occupants by video alone need review. Who went into which areas in person?”
She opened the old-address table from that morning. Material preserving the lower level’s location; plans losing its room numbers; now a picture that changed places. Missing a person did not necessarily require removing a wall. Let people trust incompatible sheets separately, and the result could be the same.
That thought did not establish how an offense had been committed. She folded away the explanation growing too fast in her mind and put the two doors they had actually seen side by side.
A site staff member requested a check of both cameras’ present appearance and cable labels. Doun accompanied them only to mark where his recalled route matched actual lines. He touched no preservation markers and opened no cabinets.
Seorin stood outside 214 again.
The line of dust beneath the door still had the break she had made by opening it yesterday. Width and position matched her photograph. Today’s dust was no longer yesterday’s initial condition. They needed to record what a single inspection had left behind too.
The black dome camera remained overhead. The white rectangular camera remained in the connecting passage. Neither had walked across overnight. She photographed each model and label separately and linked them to the office pictures.
Doun looked up at the ceiling.
“Wires can change a route without moving the thing itself. The route I left was one of them.”
He finished with a breath out.
She did not tell him it was all right. Instead, she asked him to mark the sections just verified in a different color from the recalled route. He still had something he could do. An apology could not take the place of the next check.
As they returned to the office, the corridor lighting flickered. She glanced instinctively at her phone time. Doun informed the electrical worker. The access staff briefly stopped movement through that area.
Seconds later, the light steadied. Today’s flicker could not be attached to yesterday’s isolation record. Still, she almost felt the darkness on those pages in her fingertips. Half a level down, the boundary between wall and door was the first thing light took away.
She sat in an empty chair and drank water for the first time. As her cup touched the desk, the key rings chimed slightly. With her body tight, every distant noise sounded like a door opening.
She did not take that to mean she should distrust her ears. She needed to remember which door, and what she had been watching at the time. Haeun had corrected herself: she had not seen who lowered the latch. When someone frightened narrowed her own account, the questioner had to honor it too.
Doun asked where to put the cup. Seorin pointed at the empty chair, then smiled and corrected herself toward the bin. Fatigue showed in her hands sooner than she expected. She asked her company to set aside time to review the material after today’s checks. Staying longer on site did not make judgment improve forever.
Late that afternoon, confirmation of the electrical records arrived. The worker had recorded 16:00 and 16:06 against his phone’s standard time. The photograph transmission times were preserved separately. Together they narrowed the appearance of a different location on Channel 4 to around four yesterday afternoon. Without the delay status at each photograph, they still could not establish when the actual wiring or input had changed.
Who changed it, and whether 780 seconds was already set then, remained unknown.
She wrote those limits beneath her conclusion. Nor did she connect it directly to the displayed 17:56. Delay configuration and video input change might have been one job, or separate jobs.
Her phone vibrated three times. The company wanted to know whether tomorrow’s final confirmation could go ahead. She answered incomplete, attaching the newly verified location mismatch and preservation request. If someone copied her reply onto another document, she hoped its ending would travel too.
Yunjae laid a handover item on the desk.
“Here’s a document saying the areas were checked in person. Prepared at three yesterday afternoon. It needs comparing.”
VACANCY CONFIRMATION.
Seorin began at the bottom. ALL AREAS CHECKED. ZERO OCCUPANTS REMAINING. The lower level was among the checked areas.
An attached checklist contained another line.
16:04. RESTORATION DELAYED: LOWER LEVEL IN USE.
She laid the two sheets side by side.
An hour after a signature said nobody was there, a record said the room was in use.