I agree, don’t shoot a man in the back as he is running away or if they are down and not attacking.
Remember these words: “Officer, I was in fear for my life. Even after I shot him once, he kept coming so I kept shooting until he stopped.” And say NO MORE. Keep your story simple and do not stray or elaborate. There isn’t a jury in the land that would convict you.
Actually, the way I was taught is; “Officer, I was in fear for my life.” End of statement.
Optionally, “I am not feeling well and would like medical attention” as chances are pretty good that you’re *not* going to be feeling well and being forced to shoot someone has been known to cause heart attacks, especially in the older populace. Additionally, a medical checkup is not a bad idea in case there’s a court filing afterwards - and it will get you out of truly intensive police questioning for a while afterwards, long enough for you to calm down and discuss the case with your lawyer (who you should summon while you are being treated).
Better yet, say absolutely NOTHING, and have your wife say that you both were in fear of your lives. You, meanwhile, say nothing at all until you have a chance to confer with your attorney. If you are in a jurisdiction where a wife cannot be forced to testify against her husband, you're in a better position if you stand mute