Continuity mistake: When the raid starts we see a pickup explode and the bonnet flying off. Camera cuts and now the bonnet is suddenly lying on the floor. (00:35:50)
Continuity mistake: They are hanging on the helicopter's rope, then they're still fighting on the roof and the helicopter's rope is being lowered. (00:37:50)
Continuity mistake: We see Whistler grab hold of the hand rail while stood on the roof. As Michael grabs him however less than a second later he is around 4ft off the floor. (00:38:00)
Continuity mistake: In the shot where Scofield and Whistler are clinging to the wire from the helicopter, one of the bad guys gets shot and falls out of the helicopter. He falls past the wire, but they're not hanging off it. (00:38:35)
Continuity mistake: They show Michael changing his shirt and you see his tattoos on his back, but for a split second you can see his stomach and it doesn't have any tattoos. (00:39:55)
Answer: Because of coincidence.