Though hitting someone who pulls a gun on me with the car is what I'd try too, to be honest. The car is the only weapon you have at hand, and if some group of presumed armed robbers jumps on you, you need to defend your life.
I mean, seriously, what else can you do if someone points a gun at you, surely not give in and hope that he won't shoot you. Why wouldn't he shoot you anyway, he's got no reason not to. On the other hand, with his chest under your tire, it's kind of hard shooting you.
Of course it will turn out that the agents were right and the girl was lying. She probably had 200 grams of cocaine in her trunk, too. And a shotgun. No surprise there. Like the agents in that video on tv news last week where 4 or 5 of them were kicking and giving the rod to a person who was helpless on the floor. Sure enough he was a major threat with his face to the ground and his arms around his head. Good police work.
"If you pick up a brick and kill one of those pigs [referring to police] it ain't no loss."
-- Joschka Fischer around 1980 (before his time as Minister).