In the beginning of the movie when Gibb brings the sunglasses with camera in the pack of cigarettes, there are 3 scenes in which we see the camera and sunglasses being used, at Harry's house, on the way into the mall and in the mall restroom. At Harry's house and on the way to the mall, he has the cigarette pack with the opening and camera on the bottom and the image appears in the sunglasses correctly. But in the restroom shot, Harry positions the pack of smokes with the opening and camera on top (i.e. rotated 180 degrees) but the image he sees of the men coming into the restroom isn't upside down.
In the battle in the restroom, the stall door swings open and we can see marks from the tape that held the squibs in place.