If you stopped a rape or kidnapping or arson or an assault with that face full of shot the jury will see a real ugly defendant. If he is 10' from, the muzzle of the gun they may be looking at a zombie. What they won't be looking at is your family scarred or crippled by errant shots.
Good intentions will always be pleaded for any assumption of power. The Constitution was made to guard the people against the dangers of good intentions. There are men in all ages who mean to govern will, but they mean to govern. They promise to be good masters, but they mean to be masters.