eventually ran up behind Deputy Potters and used the butt of the rifle, to strike him multiple times in the head causing significant lacerations and tissue damage.
That's the WTF part for me. At 47 seconds into the vid things really fell apart and got confusing. Those two deputies ran around the same side of the vehicle, technically got into each other's line of fire, with the one guy banging away at something off in the distance, armed guy runs up on them from behind and totally gets the drop on them. Those deputies could have gotten wiped right out. Just wow -angels on their shoulders. This could have turned out way worse.
And right after that, the other dep. has to do a mag change, runs out of the frame presumably behind his vehicle, and then comes up behind the perp and dumps 15 rounds into him.
All of that is just the fog of battle.
The mistake was getting so comfortable with a carload of hooligans, and leaving the dude alone in the car in the first place.