Continuity mistake: The bullets that Leary removes from the keychain at the banquet are in a different position than they were when he put them in.
Continuity mistake: When Leary is assembling/loading his gun, the two bullets he slides out of the rabbit's foot appear to be .22 rim fire shells. The ones he slips into the gun appear to be either .32 or .38 center fire.
Continuity mistake: As Frank goes down the glass elevator and stares at Mitch, the corpse's arms go from extended out to down toward his sides.
Continuity mistake: In the breakroom scene where Horrigan is thought to have had a heart attack, the EMTs burst in and attempt to "revive" him and he shoves them away to both sides. The camera then shifts to an over-the-shoulder view, where one EMT says "I got a call there was a cardiac case." Both EMTs are present at the left and right edges of the screen. Seconds later, Frank says "Oh, I get it. Who's the wise guy?" and stands up. In that brief interval, the EMTs have vanished completely; when everyone else files out of the breakroom, laughing, they are nowhere to be seen. (00:21:15)
Continuity mistake: When we see Frank peering out of Booth's window after the landlord calls the cops, it appears to be dark outdoors with only street lamps for light. The camera then cuts to Booth viewing Frank from across the street, but it appears that it is now daylight outside. (00:08:20 - 00:09:15)