Continuity mistake: In the beginning when Deadpool is in the front seat of the cab, the passenger window is rolled half way down, although it seems to change during the scene. But then, when he pulls back his mask, the window is now rolled all the way up.
Continuity mistake: When Deadpool causes Ajax to crash, the debris around him on the ground disappears between shots.
Continuity mistake: When Wade and Weasel decide on the name "Deadpool," Wade is wearing gloves, but in the close-up, his hand is bare (and un-scarred).
Visible crew/equipment: In the opening fight in the vehicles, Wade looks at the SUV pulling up alongside. As it does, the camera recording from his point of view is reflected on the door.
Continuity mistake: When Deadpool comes back to the duplex after cutting off his own hand, he grabs a red towel off a Chevy Citation parked outside. When he enters and flops onto the floor, the towel is yellow.
Answer: We don't see what happens to Angel Dust after Colossus carries her (and Negasonic Teenage Warhead) away from the collapsing Helicarrier. Both women were unconscious and we can only assume that Colossus put Angel Dust down somewhere before returning to Deadpool for the end scenes. Her fate beyond that - perhaps escape, incarceration or even recruitment - is unknown.