You absolutely should train to shoot while "retreating", if for no other reason than you are not limiting the tools available in your toolbox. What happens if you only train to shoot while standing still, advancing, or side-stepping? Ever tried to walk backwards through a door while keeping your eye on a threat? I have. Not easy.
Let's face it, all machismo aside, what is the intended goal of an armed encounter? WIN/LIVE/SURVIVE (however you define is up to you). I define winning as "getting out a a bad situation alive, with as little damage to me as possible". If that means I'm forced to shoot a bad guy, so be it. Shoot em where they are biggest and shoot them alot. If they expire, that is up to a power greater than me.
Of course there are too many variables to list. If I need to stand ground and engage, to defend another...that is what I will do. If I am the only affected party, I'll shoot my way out. Only a fool would stand and trade gunfire mano e mano when other options exist, becasue Mr. Murphy is an optimist and he will screw you. Your gun will fail you in the middle of a fight, you will trip and fall, etc.
There aren't any chicken$hits in a gun fight. Just winners and losers.
Your opinion may vary. I suspect some will.
