"I know," Cedric nods shakily. It was an awful place. All of them were in danger then, but...that death was the hardest thing he'd ever have to watch.

"Because---because I let it happen. I was supposed to kill that monster before it had the chance to infect you, but I hesitated. And then I had another chance to help, to think of magic that might save you, but I wasn't clever enough. I tried, up to the very end, but I failed you."

He's torn between relief that they're inexplicably alive in the here and now and the crushing guilt that keeps him from celebrating that like he wants to.