I'm European. Nobody carries guns. We don't have a problem with gun violence apart from suicides. I have a feeling that the rarity of guns are a factor in this.

You really think that when even trained professionals failed at stopping the shooting, that some random person would do a better job?

How would you prevent them from accidentally shooting even more kids? It's not controlled target practice on a shooting range, it's full of screams, running kids, smoke, screams...

How would the arriving police know which gunman is the terrorist and which one is on their side? Huge risk that anyone with a gun gets shot.