Bones says "Jim he's on the edge of a nervous breakdown, if not insanity!". Given that statement by the ship's doctor, one would think it's probably not a good idea to upset Dr. Daystrom any more than he already is. But what does Kirk do? He immediately charges up to Dr. Daystom and says the worst thing you could possibly say to him at that point--"The M-5 must be destroyed!".