Fire could have come in from elsewhere. But it sure looks to me like there were at least 3 LEOs who fired rounds from their handguns at him.
When you watch the longer version, as the drone orbits around to the front of the vehicle, it looks to me like at least one round, maybe more, had gone through the windshield on the driver’s side. Which would likely mean they were already firing at him before the truck came to a stop.
That sure would explain why he came out of the vehicle so fast.
It was a classic blocked ambush. Mr. “I read the bible and Constitution in bed” former combat medic Sheriff set it up and likely positioned his men for the ambush. The driver left the vehicle to divert their shots from the vehicle to him. He likely saved the lives of the vehicle’s other occupants.