The guy just demonstrated that he's capable of committing a felony (yes I realize it can also be charged as a misdemeanor in Utah).

Hence there's no way I'm following or making contact or attempting to get closer to take a picture. This could have ended terribly if the guy got even more aggressive in the parking lot, who knows what else he was capable of.

You used the term "us" so presumably you had family/friends in the car with you. That's a massive risk you're taking by engaging with the guy once he has fled.

Stay pulled over at the spot, call the cops, and wait for them to arrive.