It is pain. That goes unsaid. It is every atom and molecule being wrenched apart. It is feeling his entire being ripped apart and not thinking, Oh, I hope I'm ginger or I'd like to be maybe a little less like a stick or even God, this hurts. It is watching three of the people he loves most in the universe in their own kind of pain. He wishes now he'd explained this to Donna who looks so confused and upset, like a little girl as she crouches. He wishes Jack wasn't being such a clinical arse about it all. Most of all, he wishes Rose didn't have to watch.
It is Rose.
It is always Rose.
She is crying so hard now, the tears flowing down her cheeks in a way he hasn't seen for years, not since they said goodbye for the last time. He feels a twinge of anger, as though she is only crying because he will change. Humans. So focused on the superficial, the cosmetic, the fleeting. She didn't seem so emotional last time, but then again, she has an idea of what to expect now. She's seen how this happens, the way it makes him weak at first, and then he begins to talk and enunciate like a completely different person. It's his curse that he remains the same man in ten different bodies, yet unable to live in the same manner.
He can forgive her for this flaw though. Back there, on Bad Wolf Bay, she'd confessed she loved him, although he'd known this since the moment they'd met. But she'd loved this him, this spindly little person in suits and glasses. She'd loved the man who babbled incessantly about 1970s punk rock and his big, beautiful Tardis all the time. She'd maybe even loved that huge Adam's apple of his. Strange girl, that Rose.
The light's made it impossible for him to see her now, impossible to see anything, really. It won't be a moment before he's fallen to the floor of the Tardis, a brand now form, a body with new wobbly bits to get used to. He can imagine it now: Donna, crying and exclaiming, "who the hell's that?" Jack will be holding Rose back, his arms wrapped around her waist in a desperate attempt to keep her from suffocating and holding this new creation, the Doctor. Eleventh one.
He closes his eyes and does the only thing he can do. He thinks of Rose. It is Rose. It might have been others lifetimes ago, Ramona, or maybe briefly, Reinette or River Song. All R's. How very queer. But they cannot rival the intensity of his love for that tiny little human girl standing there now. It is always Rose.
He thinks, Oh, please. Blonde, brunette, redhead, bald. Make me thinner, fatter, male, even female. Toss it all, make me a big squishy alien thing. Just don't let me lose her again.
It is Rose.
It is always Rose.