Rose. His lovely Rose. That is all he can think of. He remembers everything about her. How her blonde hair smelled of vanilla, her carefree laugh, and her lovely smile. She is all around him, memories in everything, everyone. When he sees a blonde woman, he turns, thinking, wishing, hoping that it is her, even though he knows that can never be. When he hears a teenage girl laugh like she doesn't have a care in the world, "Rose," is already on his lips.
The Doctor knows he will never forget her, and she is the one he thinks of when he is regenerating. It is her that his mind is full of, even when he feels as though he is being ripped apart and shoved into a new body. She is all he knows, all he loves. And she is gone.
"I don't want to go," Is what he whispers before the regeneration process; but what he means is "I don't want to leave her," Rose. His lovely, beautiful Rose.
He can never see her. Never again; even if it were possible, he would never be able to see her through these eyes. If he were to see her, it would be from a stranger's face. She would not know him. To Rose, he would just be a man. Perhaps it is meant to be. But he knows that is impossible. Because Rose is gone. And soon, he, the tenth Doctor, will also be gone.
He doesn't want to go. He wants to stay. Wants to live in this body. He misses her so much.
He is scared. Scared of life without her. Even though he has not traveled with her in months, and can never travel with her again, he knows that regenerating means leaving her behind in some sense. He cannot explain it.
The Doctor, the oncoming storm, is dying. Regenerating. Changing.
"Rose."
