It's a good job she's ahead of him, because his face blanches slightly at that. Not much. He just wasn't expecting his poor attempt at a joke, when he was on the floor of CID, to come back at him.

'Dunno why,' he says, stepping down behind her, with his eyes fixed firmly on her rear.

'They're the professionals.'

He has no doubt she'll be better, but that doesn't mean he can't take the piss.