Games : Do ghosts of zombies wander around rooms?

As we know, some zombies spawn ghosts after you kill them. These ghosts wander aimlessly around the room without attacking, when you're in living form.

Recently I saw one of those ghosts wander into a doorway and he disappeared. Sadly I wasn't observing enough to see if the number of ghosts in the other room increased.

So the question is: Does a ghost appear in the next room if it wanders through a door?