In this episode, in the scene involving 'Secrets That You Keep', DI Carlisle is seen walking across the street from a 'Doctor Who' museum. DI Carlisle's portrayer, David Tennant, currently plays 'The Doctor' in the new series.
Peter: ...which meant that when he got hit later that night, he dropped like Mr. Slinky.
Peter: It's in that head of yours, screaming at you to tell him, tell him.
Danny: Your the man, you are the man
Peter: Get back to me when you've worked on your criminal patter
The Secrets That You Keep by Mud
The Boy With The Thorn In His Side by The Smiths
Sqweeze Me, Pleeze Me by Slade
Can You Feel The Force by The Real Thing
Brilliant Mistake by Elvis Costello
Music used in this episode: