One last time. All he wanted was one last time to hold her close to him, to feel her single heart beat against him, to see that smile with the tip of her tongue peeking out from between her teeth. And he could never have it, not now. Now that he'd left her with himself, but a different him. A him that was confused and dark and terrible. The last thing he'd seen of her was the back of her head- she was in his arms, burned in his memory that way. The only thing he could really see her as, remember her as, was that girl in his arms, but not really his. The way he would remember her was a sacrifice, and the pain was terrible.
One last time. All she wanted was one last time to see the other Doctor, the brown-suited Doctor. One last time to see whatever star she chose. One last time in the TARDIS, picking out the most appropriate wear for wherever and whenever they had landed. She had the Doctor, but she needed him. Her next thought was simply that the pronouns were going to kill her.
I'm not scared, he told himself, face to face with his own death. I'm not scared. I'm alright. And as he staggered back into the TARDIS, he croaked three final words- "I'm always alright." Then the burning, the flame, the regeneration- being was irrelevant, and he stumbled back to hit the wall with a gasp. His hands went directly to his hair. Hair. At least he still had hair. Once he reached the mirror he could see that his hair was still fairly unruly, though considerably more ginger-tinted. But the only thing he could see, looking into that mirror, was that he was gone. Rose's Doctor, the Doctor he had been, was gone forever.
Years and years later, Rose was dying.
One last time, she took his hand.
One last time, she saw that familiar face bending over her.
One last time she imagined the twilight as no other human could ever imagine it.
One last time, she smiled.
And on the other side of the Void, the Doctor heard her voice whisper through the TARDIS, one last time.