But if you have called 911, and are in a locked car, and in a Shell station, and the person that you just put a bullet into is the same one that was just involved with you in a car accident, and you agreed to pull over and to talk about it, then the second bullet would not have been self defense, but evidence of intent to finish things off.
She's in a visible place and has called the cops already ~ I"m guessing the dispatcher told her to proceed to a safe place like a gas station and wait for them ~ ol' goober there probably wasn't privy to that conversation ~ but we'll see.
Most security cams are not audio-equipped. However, it will be interesting to hear how many and at what spacing the witnesses heard.