I'm repeating what I teach.
If you need to apply deadly force, to shoot someone in your home, or who is or has attempted to murder you or a loved one, it is better to finish the job.
People who have wounded or left a perpetrator alive then face any number of slithering lawyers, and in fact have lost their homes to court actions in favor of the original criminal who tried to do them harm.
When I teach home defense, I advise women to shoot until the gun is empty. Until there isn't any twitch left in the criminal.
Dead criminals are never repeat offenders.
And that is based on experiance.
Firearms are deadly weapons. They are meant to be.
Personally, I would never put "bird shot" in any rifled barrel. That is asinine in my experiance.
The OP is relating what some idiot
If your first 3 are bullets, you are that much closer to the objective, kill before being killed.
If two of those are bird shot, you wasted two shots and only pissed off the criminal who wants to harm you.
I teach to kill. And to make damned sure the job is done.
Living with the aftermath is what shrinks are for. But the key word there is "Living..."
I'd much rather console their trauma,
Than to water the flowers on their grave with my tears.
Are you beginning to understand?