Just to clear things up:
1) the individual associated with the injuries is in fact a transplant from another dojo, has never taken rank with my sensei
2) sensei is aware that everyone is afraid of this person and has tried to communicate the need for control as well as power. not working.
3) if direct verbal communication does not work in getting results, and the person in question is too strong/fast to kaeshiwaza when they are barrelling through a technique, and one still does not feel safe (can't avoid dangerous person without being obvious), is leaving the dojo the only option for kohai? sensei persisted in letting this person teach even after so many injuries -- eventually no one came to this person's class. how to resolve this without tearing the dojo apart with open rebellion?