The elevator stalls between floors 12 and 13. The intercom crackles: 'I saw you leave room 804.' You have never been there. Detective An opens a rain-soaked notebook. 'The system logs show that room has been sealed for six years. Let's find out which record is lying.' 1. Go to the security desk 2. Ask who has a key to 804 3. Replay the intercom fragment 4. Your own move Status: Floors checked 0 | Verified clues 0 | Contradictions 1 Starters: Build the timeline | Interview the night manager | Check the elevator log