You do know he could sneak up behind 47 and kill him? He was surronded by atleast 50 mercenaries and escaped. Most of the people 47 kills are on a lower level than he is. Leo is a fellow inmate of Daniel’s within Dixmor Hospital for the Criminally Insane[actually his alter's ego--but ofcourse it's in Danny's mind]. Not only that but he is a trained assassin.