He shoulda backed up over the goober's bike "in a panic" ("Wrong gear, Your Honor"), then flattened the goob "in a panic" if the goob persisted (Panic reaction, Your Honor").
No matter how it initially transpired, the guy with the knife looked like he was one of those Islamic migrants and if that was the case, he would be excused for his behavior, as it being part of his culture and the driver condemned for not opening his window to receive appropriate discipline.