I don't know. I don't see Clark as responsible, in any way, for Corben's death. He rendered him helpless, yes, but it was in no way different than restraining any other criminal. He's not the one who pulled the power source on Corben - he's no more responsibly for Corben's death than if he'd been a regular guy who'd been restrained and killed by a random drive-by shooter.
Still, he's Clark, so it would bother him and of course he'd blame himself. Especially after seeing Lucy's pain.
