Training or not these things do not happen in a vacuum, u cant monday morning quarterback these life and death events. Its more about your instincts, subconscious reactions then anything.
Men that consider themself brave find themselfs useing there wifes as a shield. Men or women u would discount,hurl themselfs into danger to shield a loved one. For every 10 that hit the ground theres 1 who would stand there and return fire. Its nothing to be proud or ashamed of its just how your body reacts. This is why law abidding citizens should be granted the right to carry, u dont know in thoses frist seconds of action who U are let alone the person next to u.
Faced with these types of situations, what do you see cops using? ARs, sniper rifles, and ballistic vests in superior numbers.
People act like concealed carry is some sort of "magic bullet" against terror attacks, but it isn't. And it really isn't fair to ask these individuals to go after criminals in horrible tactical situations when law enforcement wouldnt either! Concealed carry is best abled to defend against assailants with equal or less firepower when the defensive carry is unexpected. Someone with a snub nosed 38 surprised by an assailant with an AR carrying unlimited mags and wearing a ballistic vest isn't going to be able to take him out under normal circumstances. If he fires upon the shooter, he will be able to distract him, potentially saving lives, and likely get killed in the process. It is not the duty of a concealed carry holder to commit suicide in this manner, he has the right to make that choice. If at the time, defending himself and his family means hiding behind a pew along with everyone else, then that's what it means.
And the more people willing to lawfully carry, the better; as someone may find themselves in a situation where they can make a difference with relatively low risk (such as being to the side or behind the shooter). The guy who took down the shooter had equal firepower (AR vs AR), less ammunition, and no ballistic vest protection, but he did have the element of surprise, and was able to take out the shooter. In a protracted conflict with no element of surprise, things may have turned out very differently