The mere presence of armed people would do a lot to prevent this kind of activity.

People who are deranged, or want to make a statement, do not go into a place where the second they draw a gun they could be confronted and subdued.

They go somewhere where it can be a shooting gallery, like a school.

We don't need super soldiers, we just need ADULTS. Living, breathing, functioning adults. People that are responsible. Not children playing pretend adults being scared of inanimate objects.