So assuming it's random lack of training when he does it again seem far too charitable.
He also has a history of doing exactly this before. It's the second time he was "struck" by a moving vehicle after purposely putting himself in his purported harms way. Who knows how many times he's practiced for this murder before.
If the video somehow didn't do it, the "fucking bitch" not even seconds after pulling the trigger would put any one of us away for murder.
[1] https://www.thenation.com/article/archive/us-border-agents-i...