[John just assumes it's a joke. Although, based on that exchange between the brothers after the incident with Hart...]

If you need me to rough him up for you as an option... I'm really gonna need you to take care of my back, mate. Might be a minor infection. [Very minor. He doesn't need to check himself into hospital again. He'll be fine. Probably.]

Have you heard anything from Lestrade about what they found in the Underground?