No expert, but suspect his ‘suicide vest’ (murder vest) may have actually held 30 or 40 round magazines. A crowded room, even semi-auto, 5.56 bullets flying around, going through and hitting maybe two or three people a shot and it’s not that hard to imagine over a hundred casualties in a short period of time.
One competent shooter with a nine mm handgun might have put him down. It must have been bedlam the first few minutes.
and TWO such individuals LIKELY would have cut him down... and THREE such individuals DEFINITELY would have ended him before he got to 20.
If half of the people who were there actually were armed... the shooter would have gone to a more target-rich, defensively-limited environment.
Problem is that most of the effeminate males we have met, act more like “Ewwwh, get that nasty nasty (gun) thingy away from me, or I might pee my panties!!!”
They are not typically known for their “let’s take these bastards out...” attitude.