Video on the news shows him shooting as she's driving by him. We can take sides on this but judging just from the video it appeared she was just trying to get away, not run anyone over. The agent could have quickly moved aside.. he chose instead to quickly fire his weapon. You see him hold his arm up as she's driving by him.. he wasn't in danger of being hit as he shot that weapon. His intent was to take her out as a threat. Quick decision in a tragic situation. We can armchair this all week long but that's all it was.. a tragic outcome to a quick decision responding to someone who refused to exit the vehicle and tore off instead.