Which mirrors my concern.
The article points out not every first responder is going to be at the top of the game. Someone with an eotech mounted wrong or a magazine inserted backwards bothers me less that someone that identifies a threat and even though protocol is to issue commands they just start shooting at the "threat" due to adrenaline and bad training. This is also true for non-LE CCWers since most self defense training is to shoot the threat since, well, it's self-defense and that means the threat is obvious.
That doesn't mesh well with interdicting in an active shooter since there are plainclothes LE and other ordinary citizens maybe doing the exact same thing and even in the best-case they've probably only been trained to deal with self-defense (i.e. shoot the obvious threat vs IFF). In the worst case they're completely untrained and haven't experienced an adrenaline dump with a loaded gun in their hand before.
I understand the author's point, but it seems borderline suicidal to get involved here. Not because you'll get killed by a terrorist but because you'll get killed by a good guy or you might be the one to accidentally kill another good Samaritan. Does a guy opening fire on a cluster of AK wielding terrorists outside your field of vision look like someone shooting indiscriminately whilein the throes of tunnel vision? It seems like that would be an easy mistake to make...