There was a fatal flaw in Eliot's plan to keep Johnny contained. Mainly that, while Eliot was certainly capable of tremendous feats of endurance, he was still technically just a normal human, and he grew steadily weaker over the 24 hours he'd spent locked to his radiator.
And thanks to Ingvar, Johnny was only getting stronger.
(
Yeah, Johnny's still nasty. Content note for cutting and injury )