Continuity mistake: As the train is approaching the police road block, we get a shot behind the police cars right before the train hits them. At that point all the policemen are gone. In the next shot, the policemen are back by the police cars.
Revealing mistake: When Haywire jumps off the tower, it's obviously a stuntman falling down. And when you see his fall from above, he is falling towards a big drain. But when the scene cuts to the part when he has landed, he's lying on concrete.