I just noticed...

Maybe its just a ランダム handprint that has no signifigance to anything :]

probably a screw up.

His shrit does change from a right to a left hand from time to time.

あなた mean why does his シャツ have 5 fingers on the hand while all of the characters have only 4? I think it's supposed to be like a reference to the movie Castaway または something like that.