"She was trying to drive away" is like "they're just trying to make a better life for their kids". Having a rational excuse for your crime doesn't transform it into acceptable behavior. Can you imagine what the world would look like if "I was scared" was an acceptable excuse for violent criminal behavior? You can't falsify that shit, so everything becomes permissable if you know the password? Fuck that.

They legally told her to stop. She illegally gunned it and hit a federal officer, which is assault with a deadly weapon. He shot her dumbass. The end. Her subjective intent is irrelevant.