Go towards the end of the movie where the nasty prison governor is hauling the hero up along the steps to the room where he is going to abuse him.

The scene is shot from the other end of the prison yard to show that the fellow prisoners are all witnessing the scene.

The hero - can't remember his name - starts screaming and your eyes are fixed on the governor and the prisoner on the stairway going from bottom-left to top-right of the screen.

As the camera pans back, a sound engineer with his microphone on the end of a pole can be clearly seen running from left to right along the wall below the stairway.