It just dawned on me that this episodes core monster is a lot like Stephen Kings IT (which wasn't the first to do the whole, emotional vampire, fear eating story, that's been around for a long time). IT's final move is to get into the mind of the victim, show them their deepest fears and place them in an almost paralyzing level of terror, then feeds on the flesh to raise that even higher while having the real feast - pure unbridled negative energy from the fear created in the victim.
In this context Barney means fight. Its a northern thing. It's not Cockney rhyming slang here.... Lister is a Scouse.... The natural enemy of the Cockney.
