Glad nobody was hurt. Why did he have his gun out to begin with? I bet you could hear the collective clenching of butts in that building.
Was he immediately neutralized by a teacher with a gun?
Negligently discharged his gun*. The only accidental discharge is a gun that actually malfunctions and that is guaranteed not to happen to whatever modern weapon he was carrying.
This is why they should only hire returning veterans to guard schools, particularly those with PTSD.
Zero tolerance, this guy has to be fired. We can't have one set of rules for one class while we have another set of rules for the remaining ~~slaves~~classes.