I think excessive force is a good term to remember. Like others have said using a full auto on full auto probably should be used with multiple armed attackers unless no other weapon is available. But when you now for sure your life and that of your family is in mortal danger ALL BETS ARE OFF!!!!!! Like it's said better to be judged by 12 than carried by 6.
"When the people fear the govt there is tyranny, when the govt fears the people there is liberty."