He isn't mentally incompetent with clock management, he just has bad timing. Near the end of every quarter roughly 2 or so minutes left his gum starts running out of flavor so he needs new piece. He is scrambling around in his pockets to find the old wrapper because well he isn't going to throw it on the ground, he might step in it. Then he finally finds it, he now has to find a trash can because well he doesn't want to liter. Lord knows people would be all up in arms over that! So then he finds the trash can, he now has to find another piece of gum. After walking around asking all the assistants and trainers and staff trying to find out who has his gum stash the clock runs out and the game is going in for the half.
Don't blame him, blame the gum makers who can't make a gum last more than 15 minutes.