Ok, so Kakashi has stated that he can't move in order to dodge the incoming rusty nail, but who's to say he didn't just make a shadow clone stand in front of the nail, so he doesn't get hit?
Better yet, why doesn't he just do a Kawarimi so the nail hits like a piece of wood while he escapes and go's behind Pein, Raikiri'ing him to death.
Thoughts?