Students breaking glass, attempting to throw broken glass, choking out other students, trying to cut themselves with tacks, hitting, kicking, and biting staff. And some have been kindergartners up to 5th graders. Several have been admitted to in-patient psych units. One parent told of the student approaching his 7 year old sister with a butcher knife. They put bells on his room door so they know when he is "coming out" into the house.
Save all your sanctimonious condemnation of the police and school system. You obviously are ignorant (in the literal sense) of modern reality.
My wife was a teacher for quite a few years, first in a Christian school then in a public school. Her experiences included having her life threatened, having to deal with teens having sex in her theater, and other hair-raising episodes. If anything, those stories just reinforced my points of view on the matter.