Continuity mistake: Close to the end when Edward Norton runs up to the front of the empty building and Brad Pitt appears, he tries to break the glass door by pushing a bench into the door, but it doesn't work. He doesn't move the bench and he then shoots at the glass and breaks it. When it shows him walking through the broken door, the bench has disappeared. (02:05:10)
Revealing mistake: When Brad Pitt throws Edward Norton down the stairs, there's a shot close to the bottom of the stairs in which you can see the stunt-man's face. (02:09:15)
Trivia: When Edward Norton is putting 'Marla' on the bus, in the background you can see a movie theatre playing 'Seven Year in Tibet' [sic] (with Brad Pitt) and across the street another marquee for 'Wings of the Dove' (with Helena Bonham Carter).
Trivia: As The Narrator is watching the promotional hotel video in his suite, an army of white-jacked servants come on screen to welcome the guest to their happy place of business. Front row, far right happens to be Brad Pitt. This is in no way to further the plot, it was just a silly inclusion that no one seems to catch (as states Pitt on the DVD commentary). (00:20:17)
Continuity mistake: Check out the sweat stain around the collar of Ed Norton's t-shirt in the scene towards the end of the film where he is being interrogated by police. It keeps getting bigger and smaller from shot to shot. (02:00:50)
Continuity mistake: When Ed Norton is blackmailing his boss the thermostat changes from white to black in some of the shots. The chair moves a bit to the left too. (01:16:00)
Continuity mistake: When Tyler gets beaten up by Lou, his mouth is bleeding after the first punch. After maybe two punches Tyler jokingly claims to "get it", then he says he "lost it". Right then the blood is no longer there. (01:12:25)
Visible crew/equipment: During the police interrogation The Narrator is pinned to the table, after he gets the gun and rolls back off the table you can easily see the power pack attached to his back/underpants during the roll. (01:58:10)
Revealing mistake: When Brad Pitt is cutting out newspaper articles about Project Mayhem's mayhem, the headlines refer to their deeds, but the actual writing in the articles has absolutely nothing to do with the movie. They seem to all come from one article about some town council meeting. (01:21:10)
Continuity mistake: Near the end of the film when Tyler throws Ed Norton down the steps we get the view from a security camera, however we can see the camera we are supposed to be looking through in the top right hand corner. (02:09:10)
Answer: Most likely they either went back afterwards or chased the security guard off somehow. It's also possible with all their inside connections that they stole the body from police custody.
Greg Dwyer