Maybe he didn't drop right away.
If self-defense was justified for the first shot, then it's almost certainly justified for the second. Unless she got out of the car and then finished him off as he lay on the pavement.
“Unless she got out of the car and then finished him off as he lay on the pavement.”
That’s certainly what it is looking like to me, since there is only one bullet hole in the car window. If there are two holes in him, then that second bullet obviously didn’t teleport through the window.