[He will not overlook that complete lack of plan ATSUSHI!! But he will at least let it slide for the time being...]

If someone you really cared about lost their mind and killed someone, would you want anyone else to take on that responsibility? Or would you want to be the last person they got to see and stand against? And anyway... they have a lot of history, obviously, and it's not really anyone else's right to interfere in whatever it is they choose to do.