Deliberate mistake: In the helicopter and motorcycle chase scene, there are a few things that are not possible. A helicopter cannot hover at such a steep angle nor can it move slowly horizontally while being at that angle. A helicopter doing that at such low altitude will crash because it will tend to move in the direction the nose is pointing. Nothing in a helicopter can make it move in the way seen in this scene. Also, a helicopter cannot use its rotor blades as a cutting tool as seen in the beginning of this sequence. The moment the blades contact any object the helicopter will lose control and crash into the buildings in the sides. No room for error in such a narrow place and low altitude.