It's a long few minutes before the three of them even really think about moving. Martha's hugging the Doctor's arm with a contented smile, not wanting to let go of him and spoil the moment. Donna's gingerly holding his other arm, as though unsure he's even really there, afraid that if she'll move, he'll break or disappear. The Doctor, for his part, is on such an adrenaline comedown that until he catches his breath again he's not going anywhere.
But finally Martha's phone rings, and it's the Colonel, and she has to answer it, and reluctantly the spell is broken. Martha detaches herself from them, all professional, and the Doctor and Donna watch her straighten, pull her dignity about herself with the brown coat she still wears as she moves to the other side of the room to take the call. The Doctor's fiercely proud of her in that moment--of course he's always been fiercely proud of her, and there wasn't anything particularly special about that moment, but damn it all if his hearts didn't just lift for a second.
Then they're alone, and Donna's hand moves nervously on the Doctor's, an odd little comforting stroke that's probably intended more to comfort her than him. He glances at her and smiles tiredly, rotating his wrist to lace his fingers through hers. "All right?" he asks gently.
Donna shrugs, tries to smile, squeezes his hand. "Yeah," she says in that Donna way, where she drags the single syllable out until it's more like three or four. "I just...need a minute."
"Anything you want," he says cheerfully, some of the old manic energy starting to flow back to him. "We've got all the time in the world. Crisis averted, planet saved, everything back where it belongs, everyone in one piece--"
"Do shut up."
"Okay." He chews his tongue for a moment, darting a nervous glance in her direction. "Sorry," he whispered a little sheepishly.
"It's all right." Donna's voice is short, tense, and her hand moves uncertainly on his again.
He reaches up with his free hand to cover hers. Donna's not sure when the touch of those alien-ly cool hands ceased to be creepy and became reassuring. "Come on, Donna, what's wrong?"
She shakes her head, trying to shake it off. "It's...it's noth--well--it's just--you were really going to do it, weren't you? And then that would have been...it. The end. Finished. Finito."
"Does that really bother you?" the Doctor asks curiously. "Not like we haven't come close to death before--"
"But I wasn't with you. You were on your own. That's not fair."
He grins at her choice of words. "Not fair?"
"To you. To me. To the universe." Donna glances up, sees his face, and glares at him. "Don't you give me that smug little grin, you lanky...twig. I'm being serious." The insult lacks its punch, and they both know it. Awkwardly, Donna looks back down at their joined hands, squeezing his hand slightly. "Next time, I should be with you. Just...because. I'm your partner. That's what we do. We face all this stuff together."
The Doctor laughs a little bit, stretches out one hand to gently tip her chin up to look at him. "I promise," he says in all sincerity, then smiles brightly, proudly. "Partner to partner."
Donna smiles, sniffs slightly, blinking a few times more than usual to ward off any tears that may or may not be threatening to fall, though she certainly wouldn't admit it if they did. "Good," she says quietly. "That's...good." And with the impulsive air of a person acting against better judgment, Donna leans forward to press a kiss on his lips.
The Doctor makes a tiny noise of surprise, one hand reaching up to cup the back of her neck, and as his lips move gently against hers she can almost taste the affection, the gratitude, the pride in her that he feels.
It's no more than a few seconds, and when Donna pulls back, there's a moment where they just look at each other, smiling slightly. And it's a good moment.
But, the Doctor and Donna being the Doctor and Donna, the moment doesn't last. And that's good. Their whole relationship has been built on the cornerstone of tender moments that don't last; they wouldn't have it any other way.
The Doctor's head tilts slightly to one side, curious. "Did that do anything for you?" he asks matter-of-factly.
Donna shrugs. "Not really, no."
"Oh, good, me neither."
"Just not for us."
"I never fancy nutters anyway."
"No, me neither. ...Ow. Sorry."
It's a long walk back to the TARDIS, and the Doctor can't quite help but not be bothered by the sting of where Donna had whacked him. It makes him feel...loved.