Jack regarded Sulu with guarded eyes. He knew that they would do everything they could to make things better. He just wasn't sure that everything they could would be enough, this time. Hell, he couldn't get his hopes up again only to have them crushed, he couldn't. He knew that it was a race against time, now, to find a cure, and who knows how much worse things would get, if McCoy couldn't do anything about it, in the end. How much time did they have for the doctor to figure out whether or not he could do anything? How much time did they have...in all?

"...I can't lose him again, Sulu," he said, quietly. "I can't let myself believe you on this, and then lose him again. So I..." He chewed his lip, lowering his eyes to Ianto, sleeping deeply, lying there between them. "I want to believe you, that we'll find something, that it'll work out, that McCoy will fix this, but. I mean. If he can't... If there really isn't anything to be done..." He shook his head, shutting his eyes, not even able to put into words how completely broken he would be, after a blow like that. "I can't let myself believe you, but I'm going to try. ...believing in this, in a cure, that's all I have left. So. We can't let this take him, Sulu," he said quietly, fiercely, "we can't."