She knew this how? This guy just beat the hell out of her, is it beyond reason to think he was grabbing a another weapon in his car as she lay in the street fighting for life?
How was she to know that he wasn't finished with her? Was he going to run her over with the car? Was he going to cover his tracks by killing her?
She did the right thing - regardless of what the logic-impaired lefties in the newspaper and, apparently, the police department have to say.
Damn good shooting too, based on the extent of her injuries. She may have saved someone from the same fate at the hands of this dirtbag.