If he is quartering away and you stuck the arrow right behind the shoulder then you are getting one lung ast best and the arrow is stopping against the briskit.

On a quartering away shot you need to aim a bit farther back (closer to the rear of the ribs)so you get the rear of the near lung and the front of the far side lung. You will either get a pass thru or it will stop on the offside shoulder after passing through both lungs.