Stephen, at this point, strongly believes he couldn't be more oblivious to pain. He'd be wrong. It's only the first stages, and while the heat comes on strong, now, it'll sustain him for quite a few hours.

Not that he won't need food and water breaks.

Stephen thrashes and cries out, his voice already half-raw. He comes like a snap, like a sudden break, and he tightens hard on Nick's fingers, like he's trying to lock him inside.