Lots of good debate regarding if this guy is sane enough to stand trial or not.
I'm by no means an expert in the field of Psychology, but the thought occurred to me after seeing his "dazed" appearance in the court room if a person in that apparent state of mind could have meticulously planned and executed what he did if he did in that theater. I would think it would take a great deal of sanity to even plan the event over the length of time to procure the weapons, ammunition, the booby trap diversion details, and the body armor.
I suppose it is possible to be in that dazed state of mind afterwards realizing what it was that he did, but during the planning stages he had to be much more coherent than he is demonstrating in the court room.