He raises a lot of very good points. Evaluating the situation is the key and knowing how well you shoot are important. Shooting well under stress is a whole different ballgame though. Even the stress of training can't approach what it's like in a real situation when lives, including your own, are at stake. Being sure of the target and that there is not another shooter is important (I've seen that WalMart video he mentioned). Being sure of what's around your target is yet another problem.
Yes, some of this will happen automatically if you train enough and you can also get into "auto" mode where you suppress everything else other than the task at hand. Keeping it all organized and thought through it the big trick, then there's the aftermath to deal with. A lot of very serious things to consider to say the least.