Jack jumps at the knock, the sound breaking the stillness so suddenly that it snaps him out of his reverie with a jolt. Moving to push himself out of the chair, the pain in his back, his shoulders and knee stops him before he gets very far. He's used to living with pain, but right now, he's too tired from everything to make the effort.

Clearing his throat, he manages to raise his voice enough so that it'll be heard on the other side of the door, even if it tears at his throat to do it. "It's not locked," he says, not failing to be struck by the novelty of someone actually knocking; an implicit request to come in, instead of just barging in like the guards always did.