He can hear himself breathing.

He could swear, at this moment, that he hears his own heart.

Or maybe he's just imagining that he's got a demon's heart pulsing in front of him, just ready for the twist of his knife.

Too bad a demon'd probably like it.

He grinds his teeth together, trying to concentrate on anything that ain't that.

"You're gonna show me, Cas? Hell, if you think you've got game, why don't you go in there, give 'em what-for?"

Please.