It was good, but seriously, that was not an accident. They had sulfuric acid in a small vial with the intentions of causing bodily harm (I know they said clothes, but there is no guarantee). They should at least be held as accomplices leading towards suicide (I'm talking about Ryouka - blonde girl that lived). As for Amori (murderer), the minute he decided to kill their teacher and not simply capture her/restrain her, etc. was the minute he could no longer justify anything. He acted worse than those three girls that caused his girlfriends suicide.