If anybody did that to me, I'd be wondering if he was on drugs or trying to carjack me.
That said, I think the driver very likely panicked.
Ironically, in self-defense training courses taught by former police officers, they teach average citizens to use the car, as a weapon if necessary, to get away from an assailant.
Really? They encourage individuals to disregard commands from an individual 6 feet away with a firearm pointed at their heads? Flys in the face of what carjack victims are advised to do by LE's. Don't resist. Especially without a clear exit path.