I dunno, the sense of time at the end of the game can be pretty tight. He was open and got it off with 4.5 seconds remaining. You also have to realize that officials don't want to call a foul that decides the game, so getting a call is much less likely in those circumstances. There were potentially 2 help defenders if he drove and they collapsed well. MSU's heave came from Maryland's side of the court --not sure you can leave enough time for a rebound and not give the opposition a chance if they get it. Odds are to leave a couple seconds since you're on your side of the floor, but no guarantees obviously.
Sometimes a guy makes an incredible play.