Continuity mistake: Michael makes the target/client use a faulty pen that spill ink all over her hand. When Michael is in the bathroom and holds over the targets mouth, his shirt gets dirty of the ink from the target/clients hand. After this, it switches between the shots and Michael having a dirty and clean shirt several times. (00:10:53 - 00:11:46)
Continuity mistake: When Ricky leaves Michael's apartment he has the envelope with money in his left hand. When the shot changes, we instantly see him walking away empty handed, with the envelope lying on the table.
Continuity mistake: When Chandler's car explodes, he and Michael land prone on the ground facing the explosion. When the shot cuts, they're facing the opposite direction. (00:33:35)
Continuity mistake: When Michael is talking to Barry, Barry's hands change position with each shot. On the table, folded together, holding his glass, etc.
Chosen answer: It might not actually have one, in which case, he'd have to go down into the club and use theirs. As for showering, going to his mother's house or a gym membership would take care of that.
Captain Defenestrator