Or the teacher or another student notices the person acting in an angry way. Then a frank criticism session is engaged in with the student, incorporating "setting before the eyes" to depict the consequences of the behavior.
That doesn't seem to address the "root cause" of the anger...so no matter how much someone knows that bad results will happen, if they don't actively shift the "root cause" (by incorporating new more effective strategies) they will repeat the same behaviour. So this must have just been one small aspect of a larger "program" (one would hope).