She had meant it as goodbye. A small kiss and then she'd be gone, off to see the universe, her universe. This man who claimed to be the Doctor would never be him. She knew would try so hard to be him and to make up for every way in which he wasn't, but it would be impossible for her to try to forget the full-blooded alien that would be alone without her.
For almost a full second it was perfect, but Rose could almost remember a kiss she'd shared with her first Doctor, and this man didn't taste of time. Still, this man loved her, in some way that should be possible, and she gave him herself for a brief moment.
It was a moment too long. She should have known that the Doctor, her Doctor, her forever Doctor wouldn't understand that she would refuse to leave his side. She ran up to where the TARDIS was disappearing. She had promised him forever, come back from across the void, and he still couldn't believe her. She loved even that about him, couldn't help it.
The human male took her hand. He'd need a name. She didn't know how long he'd last, but she felt instinctively that she would be around long after he was.
Staring out at the sky as though searching for the edge of the universe, Rose allowed herself to hope. She'd made it back to his side once before, and she would again.