That guy was NOT fearing for his life. He was pissed off that she dared not obey them.

[AZJonnie]

2. I think he moved in front of the car while the agent on the passenger side told her to take off

So he could shoot her in the face when she did as the other guy told her to.

I bet money once this guy is known, people are going to come out with stories about how he's a Trump-slurping virulent RWNJ who'd been itching to kill some 'libtard' who got in his way. And like you say, probably a cop who'd been fired for doing something similar, or rejected by police academy or the military outright because he's just too violent-minded, even for them.