Let's get clear on this issue.
Maybe I'm missing your point. To keep from dropping the weapon and having it go off, should you only rack a round just before you shoot? I guess I'm not clear on what your intent with keeping the chamber empty would be. My post about the spoon was not to denigrate your comment. It seems that you are advocating not loading the weapon until you are ready to fire for fear of possibly dropping the firearm. I don't think that the fear is going to go away until the house is clear or the threat is neutralized. My point is that shotguns, typically, do not have the same drop safe features that handguns and rifles do. Therefore, in a stressful situation, the added step of chambering a round only after you have had a couple of seconds to collect yourself, get your bearings, and yes, assume a reliable grip on the gun is not a terrible idea. This is why police carry their shotguns in "cruiser ready" mode.
I think that you will be scared...obviously, especially in keeping with your "keep in mind" caveat. Training (physical and mental) will help alleviate, or at least control the fear. (Your ability to use gross motor skills versus fine motor skills under stressful situations). I could not agree more.
Train more with your wallet? That's relevant. Much like your "use a spoon instead of a gun" remark, huh ?