I have just uploaded my own clip of this scene from the show.
Here’s the back story. Eddie McKenna (Ken Stott) has just started as part-time DJ for local mental hospital St Jude’s in Glasgow. He also works by day as a double-glazing window salesman. He’s running late for his slot, so Campbell (David Tennant) decides to do the show on his behalf. Campbell had just been told he’ll be leaving the hospital to be moved to Perth to live with his aunt. He’s not keen to go, so unbeknown to Eddie and the rest of the patients, he decides to feign a manic episode. He wants to stay in the hospital so Eddie can train him up as a DJ. If he gets discharged and moved to Perth, that won’t happen.