But there is snapping, as in shouting or even, not that it is right of course, pushing a student but for the classroom to end up blood splattered seems very odd. Clearly the teacher has lost control but something very wrong has happened.
From what little I have read of this story he does remind me of a teacher who I used to work with. Eiter adored or hated by the kids, loose cannon and unpredictable but I coul never imagine this,