The receipt’s time had arrived before the hand that passed it over.
Seorin looked between the transaction authorization numbers and the hand on video. The shop owner remembered giving the receipt immediately after payment. But before paper appeared between two hands, the owner had returned toward the counter. Even “immediately” left room for time.
On the morning of November 24, the designated comparison room had permitted time records for one transaction and the bus journey. Seorin received neither customer name nor payment-account number. Only features necessary to connect a transaction with a past scene remained.
The transaction officer explained the receipt’s printed time and the authorization server’s receipt standard. Printed digits came from the shop terminal. The separately obtained authorization history used another clock. One transaction number linked them, but their times had different sources.
Seorin folded over her first line: CALIBRATE CAMERA FROM RECEIPT TIME. If camera and terminal were both wrong, similar numbers supplied no external standard. She needed that transaction’s independent authorization history, not its printed letters.
Doun paused the owner stepping outside. The receipt recipient’s face was masked. The officer explained how the provider had linked this scene to a particular transaction during preservation. Similar amount and movement alone had not decided it. The preservation-stage explanation identified the actual connection being relied on; it was not an invitation for Seorin to guess a customer from a masked face or a familiar gesture.
The owner’s contemporary note, transaction sequence and separate confirmation by the same customer matched within permitted scope. Seorin saved none of that personal confirmation separately on her phone. The designated comparison and reference number sufficed. She could assess why it was one event without possessing an identity table.
An unresolved interval remained between authorization and receipt delivery. The owner could not remember why they had gone back behind the counter and come out again. Perhaps paper had jammed. A possible explanation could not supply seconds.
“The printer often stopped then.”
“Do you remember it stopping for this transaction?”
The owner shook their head: only that it happened often. The officer retained the answer. Frustrated, Seorin left a broad authorization-to-delivery interval. An event connecting two clocks did not necessarily give one exact second.
The next material concerned the bus. A large number on its first sheet was the scheduled passing time. As Doun began copying it, the transport officer pointed to later actual position records. They did not yet know the bus ran to schedule.
The bus had passed without standing long at the stop. The officer supplied the relevant route and vehicle confirmation, marking the recording reference location on a map. It differed from the visible section’s beginning. Travel between those points required time.
Seorin erased a straight line. The road curved slightly outside the shop; the screen’s right edge lay farther back on the map. Matching filming direction and road references shortened her first distance. A stop looking nearby could appear later in view.
The specialist calculated recording intervals, accuracy and vehicle movement together. A location point was not treated as precisely marking the front of the bus. Signals and stopping were incorporated only as far as available records established.
“Then the bus time isn’t accurate either?” Doun asked.
“Having an accurate reference and assigning one second to this scene are different things.”
Seorin separated those questions. Another clock was no magic that removed error. It increased their ability to explain where, and by how much, something could differ.
By late morning, the two ranges overlapped. Transaction and bus both pointed toward a camera display behind the actual event, not ahead. That overlap could not immediately become a fixed result. The officer rechecked whether transaction-link and location-conversion assumptions were independent.
Were they counting one server twice under different names, Seorin asked? Shop authorization and transport histories followed different collection routes and borrowed no camera setting time. Still, selecting events from the same video remained a judgment shared by their review.
A second officer checked playback sections and links. The bus’s selected entry position referred to its front bumper, not a wheel. The difference was small, but Seorin’s table said WHEEL. She corrected the word and checked that calculation used the same reference.
Doun waited with the paper’s edge held still. Once he might have suggested treating it as close enough. Today he asked first:
“Can the next person pause at the same place?”
The officer retained scene reference and playback position together. The picture had not grown sharper; the place to recheck it had become clearer. Seorin left the question within the actual comparison rather than copying it in large letters elsewhere.
At lunch the shop owner asked to collect food ordered earlier. Explaining supplied records had already taken time away from business. The company officer bundled further questions into the agreed afternoon call and said the owner could return now. Cooperation must not surrender an unlimited day.
Seorin followed to the door with thanks. The owner did not want people discussing the shop as a secret place. She explained no scope for public naming had been settled; the material remained restricted. She promised no impossible control over every future rumor.
Back inside, Doun almost discarded cold tea, then looked for management instructions. Small actions kept stopping. She nearly asked whether he was excessively cautious. Today was not a place to judge his feelings. They washed their cups and opened another sheet.
That afternoon they decided how exterior order informed existing witness material. The removal vehicle’s passage linked with the worker later going to the window. But the worker had never said the move was immediate. Time spent adjusting the transport support remained unobserved.
Seorin widened the table’s tight bracket again. Better exterior timing did not shorten a witness’s observation gap. They could narrow the vehicle’s passage more than before. They still could not narrow the exact time of a hand at the blue door.
The designated desk received that distinction. She checked her report title so tomorrow’s question would not become “Did you close the door at that time?” EXTERIOR PASSAGE TIME COMPARISON replaced the provisional LOCKING TIME ESTABLISHED.
No separate call went to Haeun. The family’s request for a break from documents remained today. New material did not require daily calls to everybody involved. Necessary changes could reach agreed recipients through support staff.
Meanwhile the company officer reviewed another site report. Checked copies handled explanations that did not require Seorin. Building work around the idea that everything stopped without her meant correcting her errors would repeatedly disrupt other jobs. Actual delegation had made today’s comparison time possible. Explanations that needed no new judgment from her had actually gone to somebody else, using the custodian’s checked material. Her concentration here therefore did not depend on pretending the other site’s report had stopped needing work.
Late afternoon brought a provisional explanation: the two currently secured external events supported a camera display a little over two minutes behind reality. Final bounds would follow review of event links and original storage units. Seorin did not add two minutes throughout past footage.
“Would it be the same three days earlier?”
“These records don’t tell us. The comparable period on that date and other dates must stay separate.”
She changed THIS CAMERA above her table to COMPARABLE SECTIONS ON THE RELEVANT DATE. One clock did not necessarily retain one constant error.
Original configuration material included power-restoration and clock-correction checks. Maintenance records of actual adjustments were pending. Today’s accurate clock could not erase past error either. Today’s external references reached those particular past events.
Seorin removed her wristwatch. She had seen too many digits. Doun did not lay his beside it. Even as a joke, two watches on a desk could not replace that device’s time that day.
“Don’t you need mine?”
“For today’s finishing time, yes.”
He checked the agreed equipment handover and stood. Even wishing to see every record, he had transport work and somebody actually waiting. He notified the desk when he could arrive and received confirmation.
Seorin closed the summary with the remaining officer. Bus schedule and actual records, receipt print and authorization receipt, playback position and display time were separately linked. No single number finished it, but fewer questions remained than yesterday.
Before departure, preservation staff brought relevant maintenance history. A check noted that the displayed clock had previously run slow independently of any relay delay. Battery replacement was recorded later. Nobody had measured its exact slowness each time. A later replacement date could not turn the earlier maintenance note into a continuous record of seconds lost. It explained something worth examining without supplying the exact correction they were still checking through outside events.
She did not lay that note over the comparison as a substitute. Maintenance suggested a cause and period; external events narrowed actual error. The two sheets stayed beside each other so neither supplied the other’s evidence.
A support-desk worker asked whether two minutes differed much from thirteen. They must not add them into fifteen, Seorin said. The shop footage never passed through the site buffer. Combining another device’s clock and transmission path would lose the external reference they had found.
She listed tomorrow’s explanation: deliberately selected 780 seconds; clock errors belonging to each device; intervals nobody observed. After correcting numbers came the task of not adding different people’s mistakes incorrectly.
As she put away her phone, the company officer messaged. One existing question draft still said SUBTRACT THIRTEEN MINUTES FROM ALL VIDEO. It had separately quoted the illustration title DELAYED DISPLAY from her original explanation.
Seorin lowered her bag. On the day they found an external clock, device numbers were not the only correction. The route carrying that wrong number into somebody else’s questions must stop today too.