"You own an inescapable fucking dungeon," he reminds her. "At that, you would have to take me out of the inescapable dungeon to try any especially creative means of killing me. The efficient thing to do, if you spare not a thought to my comfort - and I see no reason why you should - is to stab me in the heart and lock me away and destroy the key so I can never be retrieved. Though there be but few things I can think of worse than the life I live now, that same life locked in a forgotten dungeon is one of them."

They have reached another door, or something like it; he's stopping and touching the walls again.