oa How about a ghostwriter writing a deleted scene for an offscreen character?

In a Woody Allen film we see a simple street scene in New York. It looks like a continuity shot, just made to provide a link between the previous and the next scene. The dialogue we hear seems to be taking place off screen. But the camera keeps on filming longer than we expect. The disjunction between image and sound suddenly vanishes when it turns out that the dialogue is between two people who have approached from a considerable distance. They are in the centre of the picture but nonetheless off-screen. Everything that was off-screen now suddenly appears to belong to the film. A series of drawings returns the scene to the storyboard. The location is based on film images of the same place but 42 years later. What if a voice should again pop up, not speaking to the viewer but to somebody who is also off screen? What might happen in the margins of the work, should the work also continue off screen?