Bradley Walsh credited as playing...
Graham O'Brien
- Graham O'Brien: And... so's Polidori. I lost him.
- The Doctor: You had one job.
- Graham O'Brien: Yeah, made more challenging by his ability to walk through walls.
- Graham O'Brien: Oh, come on, Doc, this is where you jump in with a rational explanation. I mean, ghosts don't exist, right?
- The Doctor: Unless they do.