I was not referring to any specific and expensive training when I gave my opinion that I feel it is important that persons in these situations have more training than just shooting at targets. It would be nice if everyone could have extensive training from experts and money was no object. We agree in that area, that for most that is not an attainable goal.
It is possible to train under simulated conditions of stress, reacting and shooting with an elevated heart rate is valuable and an easy scenario to achieve. In a shooting in a confined area such as a sanctuary with people running, yelling and so on, any training done under like conditions with the heart racing will be a plus.
Concealed is indeed concealed, but nothing is perfect. A few weapon retention techniques learned well and practiced often is worthwhile.
I'm not sure how to answer "why is it that when church is mentioned there seems to be thoughts of casualties from stray rounds." I did not write that in my opinion on the subject and I do not find that in the story about the California churches? Whether it is a shooting at a church, a home, a school or wherever, by LE or a CCW holder, it is my opinion that training gives the good guys a better chance at success.
CCW holders have indeed acquitted themselves well in shootings and there are LE who will not train past what is required as stated, no argument on that. CCW holders or cops that take training seriously are, in my opinion, a better person to have at your side when it hits the proverbial fan.