Oh, Ianto can tell that John is mad alright. But he holds fast to the other man's wrist, waiting until he's finished struggling against his grip before he glances up at the other man, clenching his teeth against his pain and anger each in turn.

"I know what they're meant to be for," he replies, meeting the other man's eye for a long moment before glancing back at what he's doing. "You're hurting yourself by tugging it around like that."

It's a statement of observation, of course, because he can feel it. Even as drugged up as John may be, it's still not enough to numb the pain away. Definitely fractured, Ianto supposes, a little queasily.