Ah. His first mission since Lisa and they played 'who's the last person you snogged'? It all sounds painfully awkward.

"Sounds like some of my reconnaissance missions. McKay likes to keep a running tally of his lifetime radiation exposure and tell us all about it."

Which makes for cheerful commentary. John has found, though, that McKay's background chatter is a good sign. It's bad when he goes quiet. Ianto seems to be similar in that.