i. to outrun my lonesome ways
It's the simplest thing in the world, kissing Miss Martha Jones. It's the only thing there is to do, it's necessary, it's going to save them all - well, maybe not him, but everyone else in this hospital, so he doesn't even pause to think about it.
She rocks in toward him, and he can feel her pulse in her neck, beneath his hand, fast and human, her skin so warm it almost burns. The kiss lingers longer than it has to, not as long as it should, and then he spins away, racing off down the hallway.
Later, he tells her it's just one trip. He tells her she's not replacing anyone. He tells her he's happier on his own, because having someone with him complicates things. Because he's not ready to lose another person who means something to him.
She tells him she's not interested in him, and on reflection, that's where they went wrong, because it didn't occur to him until much later that both of them weren't quite honest then.

ii. let's talk about spaceships
Martha's never met anyone who talks as much as the Doctor does.
They'll be running for their lives and he'll still be explaining the life cycle of a time fly (which somehow, she had just thought was a horrible, horrible pun, and she vows never to make that mistake again).
Or they're spending the night in some sort of lodge on an ice planet where the ambient temperature is about twenty degrees below zero, and he's chattering about how the planet's been drifting slowly away from its sun while she's curled up in several furs, considering sleeping and wondering if she'd stop shivering if she did.
Or in the middle of a conversation about her family, he'll start to say something, and stop, and then find something absolutely fascinating about some bit of local technology or something, and just go off on a tangent Martha can't quite follow, and doesn't really want to because she's still trying to work out what it is he almost said.
Martha's never met anyone capable of talking so much and saying so little.

iii. when God left the ground to circle the Earth
Martha's learned things in 1913.
That emotions are nowhere near the top of the Doctor's list of priorities, if they even cross his mind.
That John Smith took his tea with one cream, one sugar (the Doctor used to have sugar with tea, rather than the other way around).
That loving someone doesn't mean you can't hate them a little too, as she worked up lists in her head, all the things she wanted so badly to say to him when he came back, and knew she never would.
That she never, ever wants to wear a dress again, at least for a good long while.
That if you stand in the TARDIS, and are very quiet, and listen, there's a sound almost like singing, soft and far away.
That standing on her own is not nearly so hard as she'd imagined, when it's the only thing left to do.
That the Doctor's like a storm, wild and mad and he doesn't mean to but he can't help but leave things a little broken when he leaves a place, even if he leaves it better as well.
That she loves him anyway, and she'd rather be following in his wake or standing at his side than anywhere else in the universe.

iv. your ship may be coming in
Martha never was good at deadlines. When she was in school, she always put off doing papers until the absolute last minute, because somehow she managed things best when she could feel the seconds ticking by, the weight of time pressing down on her.
This isn't quite a deadline. More of a countdown. But a year seemed like such a long time, when the Doctor whispered in her ear on the Valiant, and now... Now it seems like hardly any time has passed at all, and it feels like she's been doing this forever.
Seeing the Doctor again is a shock - somehow, in the back of her mind, she never expected to see him again, always thought he'd be dead by the end of the year, or she would - and she can't quite decide whether to laugh or cry, lying there on the floor of the Valiant, as time spins back to a year ago today. But the Doctor's laughing, so Martha does too, hardly daring to believe that they all survived. That they won.
Hope was the only one thing that kept her alive, that year. Belief - solid, concrete belief - is new and strange and foreign, but at the same time... just an old habit coming back, and it's all there in the Doctor's smile.

v. and I hate that you're always on my mind
Martha has never loved anyone as much as she loves the Doctor, and isn't that the problem? She loves him, but he doesn't notice, or pretends not to notice, or doesn't care. She loves him, but sometimes just looking at him makes her feel like she's swallowed broken glass, like something's tearing her apart from the inside out. She loves him, but he's never going to love her like she wants him to, and that's not fair to her or him.
She loves him. But.
If there's one thing that year taught her, it's how to walk away. And she does.
She spends the first night back home lying in bed awake, staring into the shadows and waiting for the flashing of a light, and the sound that means everything is right in the world. It doesn't come, and she finally falls asleep, while her chest aches like something's been torn away.
She'll heal, but just this moment, it hurts, and she doesn't care about the healing. She cares that she can't hear the low ambient hum of the TARDIS, that the lights around her when she wakes aren't green and gold, and that the Doctor doesn't come running into her room not long after she's awake, like he was waiting for it, to tell her with a grin just where they're going today.

vi. but when the gate swings, there she'll be
The Doctor had thought things would have changed, since he last saw Martha. They've both changed since then, grown different and grown apart, and of course he's still going to come when she calls, because he promised, but it's not as if...
Well. Things are just different now.
Except that when she lunges into his arms, and he lifts her off the ground just hugging her, she feels the same in his arms as she always did, her hair smells the same, there's the same heat of her body against his and her soft laugh in his ear hasn't changed, and he remembers he didn't just come because he promised.
He remembers all the little things he missed about her, Miss Martha Jones, and remembers why he'll always come when she calls.