You will be set upon in a quick and violent matter. If you do not respond in a quick and violent manner you loose.
You will not have time to consider ANY of the following;
1. Am I going to sweep my weapon across something I don't want to if I draw
2. Am I worried about over penetration
3. What did my instructor tell me I was leglly able to do in this case
4. The list goes on and on with all of the crap I have oft seen repeated on gun boards all over the net.
The fact of the matter is that if you attempt to consider any one of these or a myriad of other things you have read about over the years you will probably be dead or mortally wounded before you can complete the thought process.
When it comes to a violent encounter you either know or you don't. You either react imediately or you loose.
The key to winning a violent encounter is shot placement with a caliber adaquate for circumstances.
In a potential gunfight there is no room for a politically correct thought process.