I am with the cop on this one. From the video, it appears as if the guy deliberately ran over his foot.
Possibly. In any case I think it's understandable that someone might lash out as soon as they're run over.
There's a big difference between an action that's impulsive and one that's calculated with respect to the level of responsibility. It's hard to hold someone completely responsible for something they do if there's no time for them to think about it. That's not to say they shouldn't be punished at all, of course.
A person that disturbs the neighborhood after dark with screams of fright is very different from the person that chooses to wake everyone up with yells.