When Frank Templeton meets Binghamton, Captain is holding a machine gun that is pointed to the ground and being held by the right arm. When Harrigan says something about 'trick or treat' the camera angle changes and now Binghamton is holding the gun with both hands pointing toward Templeton.
When the mirror breaks as Binghamton is looking into it, for a split second you see that there is a cut out hole behind the mirror. When the glass falls away you can see the top of the cut-out before the camera quickly changes.