 FACT: When Yukio accidentally shoots his translator, he is first  seen pulling back the slide of his 1911 pistol and the slide locks  to the rear. The slide of a 1911 will only lock back if a) the slide  lock is pressed up or b) the pistol magazine inserted is empty.  Since Yukio knew nothing about firearms it is unlikely he would lock  back the slide by himself, so the pistol that accidentally shot his  friend was empty of any ammunition.