Continuity mistake: As Dalton stands inside the bank vault staring at the cash, the scene jumps from a wide, distant shot, to medium, to close-in, just outside the cage. Another robber stands just outside and between jumps his gun position shifts from relaxed to raised to relaxed again.
Plot hole: When Clive the mastermind blacks out the cameras, the detectives say later that there was a blackout period of only a couple of minutes with no footage of anyone entering or leaving. That means the from the footage just before the robbery you could ascertain who was in the bank and who are the robbers, or if nothing else narrow down the pool, simply by eliminating anyone in the bank already. (00:05:00 - 00:28:00)
Revealing mistake: During the final conversation between Detective Frazier and Arthur Case, Frazier holds up his hand with the ring on his middle finger. It is pretty obvious that the hand was inserted into the scene in post production; the hand doesn't move in a natural way and simply looks out of place.
Revealing mistake: When Detective Frazier enters the bank and tries to get the jump on Dalton Russell, they get into a struggle and fall down the stairs. As they fall down, look at Detective Frazier's head. It is supposed to be bald, but it suddenly has a full head of hair. It's quite obviously a stunt double.
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.
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)
Character mistake: The bank robbers send out a hostage and put a drawer around his neck with a note. The drawer is bugged and the bank robbers can monitor the police. The police just leave the drawer lying around on the table for half of the movie inside their mobile headquarters. This drawer should be in a forensic laboratory being checked for fingerprints and similar.
Continuity mistake: After the Detective wrestles with Dalton, and he pulls his revolver out, and he cocks it and says "you just crossed the fucking line", the next shot shows the revolver is not cocked.
Continuity mistake: Near the end, when Jodie Foster barges in to see Christopher Plummer at the barber, she has a tote bag. She sits in an empty barber chair and places the bag on the floor before speaking to Plummer. As she rises to leave, she picks up the bag, but when the shot cuts to her just as she walked out the door, she is no longer carrying it. Both hands are clearly visible as she buttons her jacket, and the bag is not in either hand, nor is it slung over her wrist or arm. It is simply not there. This particular shot may only be visible in the theatrical and widescreen DVD versions, and not in an edited and "pan and scan" format.