A/N: There is no A/N for this story.

The Theory of Life, and Running for It

"Run," he'd said. He hadn't told her when to stop. She figured that bit out on her own. Maybe he should have kept telling her that, yelling it after her, pleading with her to keep going, run for her life. Maybe he should have said it again, after all that, lying on the floor on the smashed coffee table with her on top of him and enjoying this dangerous game far, far too much. Maybe after discovering her name. Run, Rose Tyler. Maybe instead of asking her to come with him. Maybe she should have kept running, away.

It didn't really count as saving her life when he knew she was going to die in the end anyway; did it?

And did it matter? What was the point of all his good intentions, and why did he have them where she was concerned? What was it that drew him to her, what was it that drew her to him, why did they breathe in exact time together, and why on earth had he given her that red bicycle when she was twelve, when he knew she was just going to fall over and hurt herself—

Make the pain worth it.

It was what he told himself when he first took her into the TARDIS. He loved the look on her face as she stared, open-mouthed and unabashed, at the odd wonder of it, the shine of metal that never knew Earth's core, the structure like a giant tree, limbs arching away above them to support the far-off roof. If she looked up and squinted she could see the telepath-moonroof. If she squinted hard enough she could probably even make it work; it was more susceptible to humans' thoughts than he'd thought it would be when he installed it. All this technology that she'd never even dreamt of, and instead of assuming, as was plausible, that he was some daft runoff from the MI6 or the CIA or some other Capital Letters, she leapt to the conclusion that he was instead some daft runoff from an alien planet. A conclusion that was right, of course, and she asked about it to make sure, which he appreciated.

"Is it alien?"

"Yup."

"Are you alien?"

"Yup." He added, quickly, "That alright?" It was meant more as a challenge than anything; not that he expected her to object to his provenance, exactly, but he wouldn't put it past the British to disapprove of anything if it interfered with their worldview.

And she had said, "Yeah," far more quickly than he expected. And he smiled. And she smiled. And they both went and saved the world.

She hadn't stopped running; he could take her hand in the knowledge that she would follow him anywhere, at a run, at a walk, at a skip and a jump, hopping, whatever, it didn't matter in the least. He'd dangled the universe in front of her and, like any worthy person, she had reached for it.

She'd gotten settled into the TARDIS with more ease than he expected, as well. His wonderful timeship seemed to accept her without question, even made things simple for her at first. He usually looked forward to watching his companions try and find their way around, before they learned the ins and outs, the intricacies of negative space, the touchiness of the sentient ship and how she didn't like people to stomp down her corridors, and how she only wanted the Doctor's hands to slip caressingly across her motherboards. But the TARDIS took to Rose, and lit arrows in flashing lights to direct her to her room, which, incidentally, was across the hallway from the Doctor's own. He saw her to it, the first time, and left her to arrange herself— though come to think of it, she'd joined this merry madness with only the clothes she stood up in— while he walked back to the central pillar in the main room, and pressed buttons aimlessly.

So what's this, then? She pulled the fire escape. She— I admit— rescued me, a bit. Helped a bit, she did. She knows— gymnastics? Her hair is blond. Her eyes are brown. Her name is Rose. What's this, then? Rose and the Doctor.

I could show her around, a bit—

Already the feel of her hand in his was familiar, although he could still imagine that he didn't miss the pressure of her palm. He flexed his fingers, staring at them in some wonder.

Run—

Rose emerged from the hallway behind him and to his left, stepping carefully, feeling the rough of the metal grate beneath her all the way through the soles of her shoes, reveling in the cold, clear, slightly metallic smell of somewhere sheerly, purely different. She was vaguely aware of having got through more adventures in one day than she'd been through in the entirety of the rest of her life, but was currently busy eyeing the man— alien— person— currently busy eyeing the Doctor, who had brought her through it. It occurred to her that yesterday, when he told her to run, she hadn't really stopped running till just now; she'd run to this ship, this TARDIS. She'd run to him.

He looked around and grinned at her, flipped some switches.

"Well, Rose Tyler— where do you want to go?"

"We can go anywhere?" she said, still not able to quite believe it.

"Anywhere. Anywhen. Anywhere and anywhen, both together, each apart, whichever your heart desires." That grin is really something. "Past, present, future, though present is a bit of a subjective term really. Here, there, and everywhere. Beatles tune. Its yours for the taking, all you have to do is choose."

"Future," she said, without really thinking about it, because in her mind she was already sure that there would be many more chances to find out where she really wanted to go; all she had to do is choose. And that grin—

She barely paid any attention to the movements of his fingers, until he started banging on the console with a sledgehammer, and then she laughed to see the difference between one hand, banging away, and the other smoothing, soothing, petting the underside of the central pillar. He laughed with her.

"A bit S and M, your ship?" she asked him, teasingly.

"Hurt and comfort," he answered with a grin, that grin, that grin, eager and bright and conspiratorial, drawing her with him anywhere he chose to go, drawing her as sure as his hand on hers. And perhaps its not really her choice after all, but it doesn't matter.

They're going to go to the future, at the moment; but mostly, they're just going to go.