I can't show that all law enforcement officers are taught this, but I would imagine almost all are. I'm certain this agent was since it's written in DHS publications. When I took BLET way back in the 90s, I was taught never to get in front of a vehicle that you stop or a vehicle where you are confronting someone inside. It's a pretty basic concept.
@BPPLEE can probably confirm this as well since he once worked in law enforcement.
It is.
Except where otherwise required by inspections or other operations, Authorized Officers/Agents should avoid standing directly in front of or behind a subject vehicle. Officers/agents should not place themselves in the path of a moving vehicle or use their body to block a vehicle’s path.
Authorized Officers/Agents should avoid intentionally and unreasonably placing themselves in positions in which they have no alternative to using deadly force.
The subject vehicle is the one that Renee Good was in. It doesn't matter if it was running or not, he should have never walked or stopped in front of it while she was still inside the vehicle.