"If I even believed this was real, I might have all that, yeah. But you know what I don't have? The Ponds. All of time and space. MY TARDIS. Who cares about forever with this face, forever isn't promised to anyone, you know. If this is all real, of course I'll talk to River before I go, few others. But I've just had hours of trying to stay in one place, Rose Tyler, and I won't have it again. If that is how time passes for everyone else, I'll just as soon get back in my Tardis, thanks all the same. All of time and space, everything that was, everything that will ever be, and you think I'd just stay in one place, let it all pass by?" Watch the people he loves grow old? He couldn't. He wouldn't. He refused. Utterly refused.

Bad enough waiting for the monster with Van Gogh. Then the black boxes and sitting for what felt like centuries on the Ponds' sofa. Just to sit around here and watch everyone die? Thanks, no. There's a whole universe full of things he's never seen out there waiting for him. New friends to meet, new kinds of pudding to try, new places to run.