After Gibson shoots Stoney through the head, and Billy crawls toward him, Stoney can clearly be seen blinking as Billy yells at him.
(at around 1 min) After the crash in the tunnel, a lady gets out of her car and demands to know "What sort of driving do you call that? It's out..." then a gun is pointed at her and her mouth drops open and moves no more, but we hear her voice carry on - "...rageous - you shouldn't be allowed on the road."
In the underpass after the crash Michael Caine is hit in the face with a gun nut he has no mark on his face.