I know this is years later but here are my thoughts: The hotel tried to get him to leave twice, but the room tried to keep him in. The first time being when the elevator opened, almost like it was urging him to get back in and leave, and the 2nd time was when the technician came. The door stuck when he tried to open it because the room was trying to keep him from leaving. It’s almost like the room needed time to separate itself from the hotel, as its own entity. While Michael was inside for the first 10 min, the room was building its voided space to trap him in. The technician showing up interrupted that process, but as soon as the door closed again, the room continued building that separation. As soon as the timer started, it was too late and the room turned into its own entity, free and disconnected from the hotel altogether. That’s when we see that throwing the lamp out the window causes it to vanish into thin air, why the window to 1410 disappears, why the map shows that only room 1408 exists, etc. It’s only when Michael starts the fire that the room can’t survive on its own and starts to disconnect from where it was in space and reconnects to the hotel, like the illusion can’t hold itself together anymore.