The Sixth Footprint

The ceiling collapses in ninety seconds.

Igyeol didn't watch the counter. On the eighth floor transfer platform, the main passage ran twelve steps straight ahead, and the drainage groove sat under the left wall. Water flowed along the groove to the right. Footprints stayed only where feet had stepped in that water.

The official rescue count was five. The wet floor held six lines.

One line had a shallow heel and a deep forefoot. It was the print of someone walking with a limp.

"Surveyor, check the exit." Saebyeok counted three breaths behind his shield. "Main passage. Twelve steps. If anyone falls, we drag them out."

"Left, two bays over." Igyeol pointed behind the equipment case. "Breathing, over there."

Saebyeok's shield turned back half a hand's width. The main passage's diagonal line narrowed by exactly that angle.

"Not on the map." Saebyeok spoke first, judgment before anything else. "Behind the drainage groove is a wall. Agency blueprint, revision three, eighth floor left side, sealed."

"The blueprint doesn't record which way the water runs." Igyeol didn't erase Saebyeok's judgment. She just asked for one more piece of evidence beside it.

Igyeol bent her knee and pressed the back of her hand to the floor. The water wasn't running straight to the groove. It pushed out once beside the equipment case, then curved back into the groove. The push was two steps wide. Water didn't bend out like that off a wall.

"Dohyeon."

"Nothing on the sensor." Dohyeon wiped the screen twice. "No echo, no heat source, wall thickness even, humidity only three percent higher. That's a wish, not data, Surveyor."

"Then one more sample."

Saebyeok looked at Igyeol from behind his shield. His eyes were counting down how many seconds he had left to object.

Dohyeon paused for a moment. His face looked like a man handed his own sentence back. He shut off the sensor and pressed his forehead to the side of the equipment case.

"Two sounds of water." No decimal point attached to that sentence. "One in the groove. One further down."

The ceiling dropped thirty centimeters. A light lost its angle and swung across the drainage groove. The ripple folded twice beside the equipment case. Water that hits a wall only folds once.

Gang Dohun looked back from the mouth of the main passage. He was the team's fifth member and its comm relay, and the only one on site carrying an Agency terminal.

"Go ahead, out." Igyeol said. "Count us at the end of the passage. We're six."

"We're five." Gang Dohun corrected her. There was no malice in it. His terminal showed five, and he said what he saw. The five were the registered rescue personnel: Igyeol, Saebyeok, Dohyeon, Mirae, and Gang Dohun himself.

Igyeol didn't answer. Answering meant explaining, and explaining would erase the twelve steps.

Saebyeok pulled the shield off his shoulder. No one had ordered it.

"Ten seconds." Saebyeok wedged the bottom edge of the shield into the doorframe behind the equipment case. Metal bit into concrete. "Surveyor, this folds in ten seconds. When I say stop, you let go."

"When you say stop, I let go." Igyeol drew a short line on the floor with the tip of her baton. It marked where the shield would fall back to.

"I'm not going past that line." Saebyeok said. "If you go past it, I pull you out. No matter what you're looking at."

The shield pushed the wall. The wall retreated by two steps' width. From inside the black gap, a hand grabbed the edge of the shield.

It was a hand that wasn't on any list.

Forty three seconds before collapse. The gap was two steps wide on the inside too. Facing your shoulders forward, only one person could pass through at a time. The woman's left foot was wedged between the floor and a bent pipe. Behind Igyeol's back, the shield creaked.

"Six." The woman said. Her breath cut in half, but the number didn't cut. "There were six of us here at first. Count again."

Igyeol paused half a beat. Whenever she asked someone's name, she was always that late.

"Name."

"Jin Yura."

"Jin Yura, where is your foot caught?"

"I don't know. I can't see it." Yura struck the floor twice with her palm. The two intervals matched. "Knock here and the sound goes thin. Not here. The thin side is hollow."

Her voice was pressed down with fear, but her hand never lost the beat. Igyeol took that beat as information.

Igyeol pressed on the thin side. The pipe wasn't resting flat on the floor. Only one end was propped up. The spot for a lever was outside her ankle.

"Officer Saebyeok, shield angle ten degrees. Left."

"Eight seconds." Saebyeok tilted the shield left while reaching his right hand back. He made the shield and the rescue one motion. "Yura, answer if you're alive. Don't grab my hand, grab my forearm."

"Forearm." Yura repeated it exactly and grabbed his forearm. It was an echo that confirmed her own part in this.

Igyeol drove the baton in under the pipe at thirty degrees. The moment the weight shifted, the pipe lifted five centimeters. Yura's foot didn't come free. The angle was right. The direction was wrong.

"Five seconds." Dohyeon counted from outside the passage. A name followed the number. "Five seconds, Saebyeok."

Yura struck Igyeol's wrist. "The other way. When I got pulled in earlier, it pushed this direction."

Igyeol changed direction. More precisely, she was told to change it. The pipe turned the other way and her ankle slipped free. The fact that the direction the rescued had pointed out beat the surveyor's own angle reached her fingertips before it reached her mind.

"Stop."

It was Saebyeok's voice. Igyeol let go. She didn't ask why, and not asking made her that much faster. The top of the shield folded and the doorframe dropped twenty centimeters. Once the three of them rolled out, the side passage sealed shut, two steps' width and closing.

"Passage lost." Saebyeok looked at the folded bottom edge of his shield. It was his equipment, and his own call that had wedged it there.

"We lost a passage and gained a person." Igyeol said. It sounded like comfort, but she was running numbers. Yura's left foot had been added to the remaining twelve steps, so the pace had to be redistributed.

"Give me an order, not a calculation." Saebyeok swung the folded shield onto his back. "Who's in front and who's in back?"

"Main passage." Igyeol said. "Twelve steps. Yura can't use her left foot. Saebyeok, right side. Dohyeon, left. I'll count from the back."

"If you count from the back, you can't see the front."

"Saebyeok watches the front."

For the first time, Saebyeok moved without answering. That was agreement.

Six of them ran. Five lines were drawn across the wet floor, and one more line behind them. Igyeol counted three things as she ran: four shoulders ahead, one weight hanging off her own arm, and herself.

On the third step, a ceiling panel fell on the left side of the main passage. Saebyeok shoved the team right. Yura's left foot touched down by exactly that pushed distance, and she made no sound. She knew that a sound would make the team slow down.

Gang Dohun raised his hand at the threshold and counted heads. His mouth counted to five. His eyes counted to six.

"Yura, if it hurts, say it hurts." Saebyeok said as he ran. "If you hold it in, I get my math wrong."

"It hurts."

"Slowing down. Spending four seconds."

They spent four seconds. The threshold was on the other side of those four seconds.

Six seconds before collapse. The headcount at the exit antechamber was stuck at five.

Yura pressed her wrist to the terminal. The tag didn't read. Twice, three times. The screen said five.

On the third try, Yura pulled her hand back. It wasn't the speed of surprise. It was the speed of habit.

"Has this happened before?" Igyeol asked.

"I don't know." Yura turned her bracelet to show the inside. The last digits of the engraved number were scratched out. "Sometimes it reads. Sometimes it doesn't."

Igyeol looked at the scratch. She couldn't tell if it was a nail mark or a scrape from a wall. She wrote down only the fact that it couldn't be told apart.

Mirae stood outside the passage holding his terminal upright. He hadn't gone in. His job was to photograph the ground people had already crossed.

"Filename first." Mirae said. "Eighth_floor_transfer_headcount_05_39. Great. Just great."

"Counting body heat." Dohyeon read the thermal screen aloud. "One, two, three, four, five... six. Six. That's not margin of error."

"Log terminal." Igyeol said. "Counter and floor, one frame."

Mirae lowered the terminal. The number showing five and the six lines of footprints landed in the same frame. The shutter clicked twice.

"Original's intact." Mirae said. "Don't upload. Just store it."

"Surveyor. What is this."

"I don't know." Igyeol said. She wrote that same sentence into her notebook, word for word. She had no plan to erase it.

The door came down. Six of them crossed the threshold. Igyeol looked back one last time. On the dry concrete, only one set of wet footprints remained. They were Yura's. The other five spots had already dried.

"Confirm names." Igyeol wrote in her notebook. She drew six boxes and filled five. In the sixth box, she wrote Jin Yura. It was her own handwriting, but that line didn't exist on the terminal screen.

Mirae photographed a page of the notebook. Then he looked at Yura.

"Jin Yura. How far can this photo go?"

Yura thought about it for a moment. Her expression suggested she didn't think this was a question anyone asked a rescued person.

"... I get to decide?"

"Decide." Mirae said. "If you don't, I end up deciding for you."

"Then show me the photo first. Not the Agency."

Mirae turned the screen. Yura pointed at the part showing her footprints and pushed away the part showing her face.

"Then what about the Agency?" Yura asked. "If the Agency sees this, will they fix it?"

Mirae lowered the camera. Dohyeon folded up the thermal screen, and Saebyeok pressed the shield handle twice. None of the three had an answer on hand.

Saebyeok stood beside her. He was still holding the folded shield.

"Surveyor. Earlier, when I said stop, why didn't you ask why?"

"Because you said stop."

"Keep doing that." Saebyeok pressed the velcro on his glove twice. "I said ten seconds and it folded at eight. My math was wrong."

"Then I'll write down six seconds next time." Igyeol crossed out the ten seconds in her notebook and wrote six. She corrected the number instead of apologizing. "On the next entry, the shield timing is Saebyeok's call. Not mine."

"That was already my call." Saebyeok said.

"Then I was just slow to admit it."

Yura sat with her back against the wall and spread her fingers. One, two, three, four, five, six. Then back to one again.

"It was six." Yura said. "I counted."

Igyeol watched those fingers. A hand that went to six and came back to one. She underlined the sixth box in her notebook. It wasn't an underline for an answer. It marked where she would ask next.

Dust fell from the ceiling again. The eighth floor was sealed. But the vibration under their feet was rising from below.