Okay, maybe it was on that rooftop where it first occurred to him, a little seed in the very back of his mind, some subconscious whim that made him turn around, open that door back up, and introduce himself.
"I'm the Doctor, by the way. What's your name?"
The Doctor. It wasn't much to go on, but if she wanted to search him out, track him down, it was one of the best leads he could give her.
Maybe it passed through his head for just a nanosecond when he saw her face on the other side of that cat door, knowing what a rare beast real coincidence was.
But not really. Not willingly, not consciously. The war, still so fresh to him though it was such a long way and a long time from this place, had changed him. He was such a different kind of Time Lord than he had been. And what kind that was, it was clear, was alone. When she pulled open her door and stared at him like he had a third eye instead of just a second heart, he was still convinced that this time, he would stay alone. Forever. It was safer that way, safer for everyone involved.
Those hearts didn't lift happily when she pulled him inside, refusing to let him leave. He didn't wonder if she was a history buff, or how big those mascara-ringed eyes would get if he showed her an electromagnetic storm or a great, gauzy, pink and blue nebula up close. He didn't look at her last name on her mail out of anything more than fleeting curiosity. He didn't do any of these things, except as something that after nine-hundred-so years of travel had become automatic, like shutting the fridge door or putting up the shields on the TARDIS. This "Rose Tyler" was nobody but another bystander, another stupid ape for whom he saved Earth so often. He mucked around her flat, did the whole disable-the-living-plastic-arm thing, and left. The time of always looking for someone to share the universe with was in the past.
But while the Doctor was the first to confess that he was very, very clever, and could do many, many things, there was one thing, besides card tricks, that he was no good at: leaving the past in the past. When he strode out of that flat and heard her own footsteps hurrying to catch up, he couldn't deny or ignore the wish that bubbled up in his chest.
She asked–nay, demanded–and he answered. He couldn't help but be proud, despite how little he knew of her, at how well she took it. She didn't shout, or cry, or contradict. She looked somehow, even as she laughed, like she was concentrating very hard.
"Do you believe me?" he had asked curiously. When she said "No," he wasn't surprised. She was clever, that was easy to tell, but she was young, and human, and oh so stubborn, you could see it in her eyes! So it was a little early, still, for her to admit, either to him or to herself, that she believed. And yet… there it was, that look of concentration behind her stubborn eyes.
"But you're listening," he had pointed out with a knowing twinkle. Her dark eyebrows bunched, and he knew she was wondering–wondering whether, in fact, she did believe. That, then, was when it had started; that was the first instant he had really wanted it.
She asked him who he was, and he told her. He never explained it the same way twice. He knew that as he held her hand and told her about what it was like to be moving, moving, always moving on and moving forward and never being able to stop or slow down, no matter how much it hurt, and clinging tight to anything or anyone you could, no matter how flimsy or transient, just to keep your mind, just to keep your soul… as he told her, he knew there was no way she could ever realize what he really meant by what he was saying. But just saying it, just feeling her hand in his own, let him imagine for a few seconds that he wasn't completely alone.
Then he let go. She looked startled.
"That's who I am." Someone who lets go. "Now forget about me, Rose Tyler," he said. He wasn't sure whether he really meant it and was trying to protect her, or if he was daring her to follow. The disappointment that filled up his throat as she let him walk away and close the door behind him didn't tell him which it was, either. As the Doctor started the engines and tried not to let the TARDIS notice that anything was bothering him, he couldn't see Rose turn around and run after the disappearing police box.
And if that had been it… well, that would have been it. The Doctor never forced anyone to come with him, never begged. It wasn't in his nature (not this time around, anyway), and he didn't like putting people in danger who didn't know and accept all the risks.
So he would have let her go. Really, he would have. Never looked for her, never asked her, never even wondered… well, never more than a little. But when he saw her having dinner with what was obviously a living plastic being, he realized he had already pulled her in too deep. He owed it to her to get her out of this. He had to bring her along, at least try to get her to come, at least for a little while. That was all. Just long enough to return her to her everyday, Nestene Consciousness-free life, where she wanted to be. It was about her, not him.
Then she pulled the fire alarm. It wasn't his idea, though it should have been; while he was busy wrenching the thing's head off, she thought to get all the gawking, screeching bystanders out of the building. It occurred to him in more than a passing way what a fine example of teamwork that was.
So yes, that was the second time, if he was going to put a pin in it, fleeing the plastic creature with Rose running in front of him instead of bringing up the tail, and that alarm sounding behind. That was the moment he didn't only think of it, didn't only want it, but he dared to hope for it.
He threw the door open to more than the TARDIS. When it only took her about thirty seconds of gasping, circling, and running out of all other options before she came in for good, he secretly couldn't have been more pleased.
Rose didn't realize that once she stepped into that police box, she began trying out for a part, but the Doctor happily auditioned her anyway. Every moment came with an invitation, and every invitation came with a chance for her to turn him down, to run away, to scream or cry or freeze up. She never did.
Some might think that moment number three, the deal-sealing detail that made him know he needed her, would have been when she swung down on that chain and knocked those store dummies off of him like so many bowling pins. It wasn't. Peeling her boyfriend off of her knees and tarzanning to his rescue was only one more invitation she decided to take him up on, one more choice she decided to make–albeit a particularly crucial one.
It was, however, the choice that got her the part.
While Rose was calling her mum, the Doctor was practicing his lines.
"Will you come with me?" he entreated a lever on the TARDIS control panel. No. Too desperate.
"I mean, if you really wanted to, I suppose… I could make room," he waffled to the wall. No. Much too reluctant. He turned and looked at his dim reflection in a display screen, practicing a careless arch to his eyebrows.
"If you're tired of all this, you know, you could always…"
He heard Rose laugh and clap her phone shut, and he looked up and quickly straightened his jacket. The Doctor appeared in the entrance to the TARDIS a moment later, leaning against the doorframe as casual as you please.
"Nestene Consciousness," he bragged, snapping his fingers. "Easy."
"You were useless in there!" she laughed. "You'd be dead if it wasn't for me."
"Yes, I would," he acknowledged. He looked at his boot toes a moment, and then back up. "Thank you." He took a deep breath and rubbed his hands together. "Right, then! I'll be off. Unless, uh…" He shrugged as nonchalantly as he knew how. "I don't know. You could… come with me."
That look of concentration returned, that wonder crystallizing into two crooked lines between her eyebrows, and oh, how he wanted to just run over and grab her hand, and laugh, and drag her off to wonderful things! He kept his composure and stayed in the doorway, though he couldn't help grinning a little as he hurried on, encouraged.
"This box isn't just a London hopper, you know–it goes anywhere in the universe. Free of charge!" Rose smiled weakly back at him, but she didn't move from her place. Then her rubbish boyfriend stuck in his oar.
The Doctor didn't listen–and Rose didn't appear to even hear."He's not invited," he clarified anyway, just in case she was going to get ideas. He licked his lips, nervous at her continued hesitation. "Whatcha think?" the Doctor prompted. Rose Tyler opened her mouth, but no sound came out, and then she shut it again. "You could stay here," he continued disdainfully, changing his tactic. "Fill your life with work and food and sleep. Or you could go, uh… anywhere."
"Is it always this dangerous?" she asked, but her voice didn't waver.
"Yeah," he answered eagerly, relieved that she had said something at last. But then that whimpering little idiot went and threw his arms around her waist. Like a child–like a little girl. He could've clouted the twerp. The lines between Rose's eyebrows dissolved, and she took a breath like someone coming up for air.
"Yeah, I can't." His face fell and something in his chest turned upside down. "I have to find my mum and… someone's got to look after this stupid lump," she added, laughing half-heartedly and patting him like the sick lapdog he was.
The Doctor found himself unable to think in a straight line. Can't? Never such a thing. Wouldn't? But why? The danger? Not her. He couldn't have read her wrongly. She wasn't a bit shaken, for all she had risked. And those stubborn eyes! Danger wouldn't frighten her. Was it just him? Had he been rude? Had he been gauche? His ears weren't that big, were they?
He felt like the universe had slapped him–for wanting her with him, for wanting not to be alone. You have made your own aloneness, reminded a voice cruelly in his head. What right have you to wish it repealed now?
"Oh." He tried to smile at her, but couldn't quite manage it. "Okay." His eyes met hers, but he couldn't see how sad and confused hers were through the sadness and confusion in his own. He backed slowly into the TARDIS, and closed the door.
He threw a switch as he walked by the central console, hardly noticing what switch it was. It would take him away from here. That was what mattered. The TARDIS seemed reluctant to take off, but obeyed after a short, concerned whine on the part of the engines. He hoped he'd end up in some outer galaxy, in the middle of a big, distracting mess to take care of.
So of course he landed on Earth, again, and in England, and less than a hundred years from the time he had just left. The family he met had a blonde girl with stubborn eyes, and he convinced them to tear up their tickets for America. He didn't stay to watch the Titanic embark--thousands of doomed people he couldn't save struck a little too close to home--but the thought came involuntarily that if Rose were here and had wanted to stay, he would've, would've gotten onboard the ruddy ship if she'd asked him to. He pushed the thought from his mind.
The TARDIS would only take him as far as the Pacific Rim the next time. The sweating English visitor who drew the Doctor's likeness into his sketch of Mount Krakatoa looked so confused and frightened when the rumbling started spilling his inkpot. The Doctor saw, briefly, Rose's frightened face illuminated by the glow of the Nestene and the feverish emergency lights. But there was a strength in the Doctor's memory of her face, where the man was simply bewildered.
"Find a safe place and just stay there," the Doctor yelled over the noise, because what else could he do? There was nothing else to do. He ran for the TARDIS with a stone in his stomach as the first explosion rocked the islands and rattled his bones, trying not to think about all those around him who would soon perish by fire.
No more distracting messes, he begged the TARDIS silently. No more cataclysms. No more thousands and tens of thousands.
The TARDIS obliged. The Doctor stepped out in the place and day of a tragedy composed of a single man's death. He recognized it quickly because somewhere else in Dallas, he was already there, two regenerations younger and unravelling some grand alien mystery. This time, resigned and a little numb, he found a place by the street and watched from the crowd.
He didn't wince when the shot was fired. He winced a few moments later, when one of the faces in all the frantic chaos brought another face to mind. It wasn't Rose's. It was his.
The Doctor looked at this great man dying, surrounded by people who loved and admired him. And he looked at himself, precisely the opposite, always the opposite. Living, but living alone. In his dismal mood, the Doctor couldn't help but think, for just a moment as he quietly toward the edge of the bedlam, that he wasn't the luckier of the two.
To his credit, after the moment had passed the Doctor pulled out of his self-pity and found he was rather disgusted with himself. This upset over a human girl? he scoffed. He pushed every other reason into a cupboard into the back of his mind (he wouldn't think of Gallifrey, of last stands, of the feeling of aloneness in his mind, that way lay madness); he was upset over a human. And it was ridiculous.
She'd said no, he reminded himself as he finally escaped the crowd. It wasn't as though he was going to go back for her. There was nothing else to it. The Doctor just had to accept that that was the end of it. He did things alone now. She had been clever and spunky and a great help, and that was all very well, The Doctor told himself very firmly, but that was the last he was going to see of the human called Rose Tyler.
For one whole second, he believed it.
That was the final moment, the one that sealed it all. Suddenly he was plowing down the chaotic streets of Dallas, stride long and defiant, footfalls solid, mouth and eyes as determined as death, a juggernaut of a Time Lord, ready to go to war with anyone who might dare to tell him Rose Tyler would never say yes, Rose Tyler would never see centuries gone or centuries yet to come, Rose Tyler would never touch the alien sand and hear the cry of strange birds and watch them wheel in another sky.
He all but slammed the door of the TARDIS behind him, and his fingers flew over the switches. This time there was no hesitation on the part of the ship--just the happy roar of the motors as it carried him back to a little alley in London, England, Earth, 2005 AD.
"Did I mention, it also travels in time?"