The Night of the Infernal Machine - S2-E14
Revealing mistake: Right after Zeno Baroda says, "M'Guigan, I'm going to kill you," he shoots at the door. Before the bullet is discharged, one can see the door is already damaged where the door is about to be shot. Also, one can see the streak (moving from the left to right) of the prop used to cause more damage on the door from the bullet's impact. (00:27:30)