[No, Cas. That's you. You you. Except Dean supposes that's not self-explanatory. He takes the phone back and pockets it.]

Zachariah showed me your future. Figured I'd better keep a close eye on Sammy. [And there's still a sting to those words, because happily ever after or not, Sam's still locked in the cage. He shrugs a little and looks off to the side.] So the world didn't end. Everyone still died, though. [He licks his lips and looks back.] Including you.

[He realizes that that raises more question than it provides answers, but he needs to take a breath before he tells the rest of the story. And maybe give you a moment to digest that his world didn't end.]