"I can't do this." She admits.

He looks at her sadly, confused and just a little bit desperate. She can barely stand to see him like this, when he looks so much, so exactly like, him. But she makes a point of looking him straight on, she owes him this at least.

"But why?" he sounds so broken, like all his love is steadily leaking out through the cracks her words inflicted.

"It's not right." Her voice cracks. "This isn't how its meant to be."

He reaches for her hand and she pulls back, just a little, just enough. His eyebrows crinkle together like she saw his do only once, only for a moment, before.

"But it is. It is now. We can grow old together, we can…"

She's shaking her head, partly to show that it's not how it's meant to be and partly so it doesn't look like she's crying as hard as she is.

"But it's not right." She repeats. "It was meant to be me and him travellin' together, forever. That's how it's meant to be. Not this, not…"

She doesn't say it, but just like she knew back on that beach in Bad Wolf Bay, she knows he knows how her sentence was meant to end. She takes a deep breath.

"I need to find him. I've done it once, I can do it again."

"Rose…" he sounds so much like him that she almost loses her resolve, but then she looks at him. Really looks at him.

She can see lines around his eyes and mouth that aren't on his face. She can see hairs changing colour slightly, barely, but different to his. This isn't him. This isn't the last of the Time Lords, or the only survivor of the Time War. This isn't who she fought aliens with or saved the world with. This just looks like him, talks like him, even…loves her like him. But this isn't him.

"I'm sorry." She says. "But I have to do this. I have to go to him. He needs me."

"I need you."

She closes her eyes before she says it "Not like he does."

"But I'm him!" he's almost yelling now, crying for real like she never saw him do. "I'm the doctor just the same as him."

She puts a hand on his chest, over his heart, his one heart. One where there should be two.

"But you're not." She says. "You're a doctor, maybe even the doctor, but you're not my doctor."

"Rose…" her name is barely more than a whisper.

"I'm sorry." She turns and heads for the door.

"You can't go back Rose!" he calls after her. "I can't let you risk ripping a hole in space and time."

She turns back to him. In this moment he looks so very much like him. Like her doctor, The Doctor. He even sounds like him too, but he isn't. She has to remember he isn't.

"I managed it once didn't I?" and she leaves.

"Rose!"

He calls after her but he doesn't run after her. It's funny, all he ever did was run. She can still hear his first words to her, back before it all, back when she was just a shop girl. She can still feel the fear and the strangeness of what had been happening to her, but most of all she can feel his hand in hers and hear his voice, his first voice, in her ear. Run.

All she hears resounding through her brain. Run, Run, Run. The Doctor needs her, he always needs her and she always goes to him. Run, Run, Run. Even when he sends her away, even when he loses her she always goes to him. Run, Run, Run. And she doesn't just hear run anymore, she hears something else, something stronger, something louder. I am the Bad Wolf. She is the Bad Wolf, she is The Doctor's companion and she will find him. Even if it means leaving him, and a chance at a normal life behind her for good. But she was already going to do that wasn't she? She left behind a normal life that first night when she ran straight at the TARDIS. And despite everything everyone has ever said to her. She hasn't regretted it once.