Other mistake: Near the end of the movie, after the cops storm the bank, all the cops walk into the vault, and as the camera follows them into the vault, you can hear the camera hit the metal vault door, and visibly see the camera shake from hitting it. (01:38:15)
Other mistake: At 1:44:31 a close-up of a bank safe deposit records document shows box sizes that don't match the sizes of the boxes themselves shown at 0:58:41 and 1:55:21. The document shows box 378=3x10, 379=5x5, 384=5x5, 388=3x10, 396=5x5 but the boxes themselves appear to be 378=5x5, 379=5x5, 384=3x10, 388=3x10, 396=10x10. (01:44:30)
Other mistake: When Washington went back to his room at the end just before he pulls the diamond out of his pocket. He unloads his Glock. The magazine doesn't have any bullets in it and there wasn't any noise of a bullet falling out of the chamber as he moves the slide back.
Answer: The hiding space was narrow and the change was unnoticeable to staff. Also, this is a large office supplies room that few people access, spend little time in, or take much notice. Therefore, its unlikely the altered space would be immediately detected. Everything was carefully planned, so the fake wall and the arrangement of the boxes and other supplies would have been considered. I have to add that it's a bit of a plot hole considering the tall, heavy metal shelving on the three sides that are loaded with supplies would take considerable time and labor to move and rearrange to accommodate building the wall and in the relatively short amount of time the robbers are in the bank. Realistically, perhaps it could be done, but probably not that quickly by one or two people.
raywest ★