P's earring disappears and reappears throughout her argument with Joe over the gun.
At the beginning of the final chapter, the Molotov cocktail Joe throws at the car envelops the entire vehicle. When the shot cuts to Joe walking away, the car behind her is only partially aflame. The scene ends with a closeup of the car burning exactly as it was in the first shot.
In the director's cut, during the opening of the chapter The Mirror, after Seligman explains that the top of the diamond is called a mirror in some languages and Joe mentions he has a mirror on the wall, you can clearly see the camera and crew members reflected in it. You even see the camera move as it pans right.