John just ploughed on through with what he was trying to say, oblivious to the Doctor's words at first, "I mean, I wanna' be able to control when I shuffle off, to the best of my ability."
The yawn though was infectious, and he soon followed suit, as the Doctor's words finally reached him. "You want I should bugger off? You old folks need your rest, that it? I'd still like to see Jack's room, but if you'd rather I go..?"