That still leaves the shooter in a bad place legally.
Time after time the courts have ruled that leaving a fight for any reason whatsoever and returning to the fight makes him the instigator of the act that resulted in a death.
I am not saying that I agree, only that it is the law.
The view of the prosecutors and judges is that once you have left, you are free of any danger to your life or the lives of those with you. Their view of the law is that you are safe enough to wait for the cops.