A thready beep-beep, beep-beep fills the medbay, and the room's three conscious inhabitants can all breathe again.

"82 over 57," says the Doctor, his fingers pressed to the pulse point bleating softly under the skin beneath Donna's jaw. He may be a mere human now, but this, at least, he can still do; all those memories of studying humanoid bodies and memorizing how they work didn't just vanish into the ether. That's something, at least.

His original self sits atop a stool on the other side of the examination table, cutting through Donna's jacket sleeve with a pair of medical scissors. The Doctor hides a smile at the thought of the fit Donna would throw if she knew. Afterward, his original self swabs the inside of Donna's elbow with antiseptic, punctuating the air with a stench pungent and harsh and chemical, and before his original self has a chance to ask for it, the Doctor crosses the medbay in several long strides, fishing the supplies for an IV and saline drip out of the cabinets.

"Will she be all right?" asks Rose.

His original self doesn't answer.

"Too early to tell at this juncture," the Doctor says, honestly. "My—"

He silently curses himself. Personal pronouns right now are…confusing.

"His telepathic blocks should help for a while," he says. "Keep her in stasis while we run some tests and look into extracting the stuff that shouldn't be in her mind."

Shouldn't be in your mind, either, a small voice pipes up in the back of his mind. But then again, you shouldn't be here at all.

"We'll do everything we can," the Doctor continues, rigging up the IV station. He sends Rose a reassuring smile. "We may actually have a small chance at keeping her original memories intact, thanks to you."

He glances up to see Rose smiling just the littlest bit, and that shuts the voice in his head right down, because how could it not? She's real, she's in this universe again, she's safe, she's here. With him. (And on-purpose, as well; she could have left him on that beach in the other universe without a second thought, and maybe he even would have deserved it. But she took his hand anyway, and even if it doesn't mean anything in the end, he's deeply grateful.) His pitiful single heart swells almost painfully in his chest and the Doctor is suddenly very glad he's not the one hooked up to the heartrate monitor, that no one can hear his galloping pulse ringing out through the room.

"Just the smallest chance, mind," he says quickly, handing the IV tube and needle back to his original self. "But, y'know. Better than no chance at all."

"Except that there's no fallback here," his original self mutters. Rose and the Doctor watch as he pushes the IV needle into Donna's flesh, medical precision executed to perfection by well-practiced hands. "If I fail at this, if my telepathic blocks don't hold up, if the scans are inconclusive or I can't locate equipment sophisticated enough for the kind of extraction we need—which is highly likely, by the way, something I don't expect her to know but you—" he says pointedly to the Doctor, voice hitching, "—you should have been well aware-of, even if your senses are irreparably compromised—if any of that falls through, Donna's good as dead."

"Well what else were we supposed to do?" Rose demands, throwing her hands up in frustration. "Just stand there?"

"Yes. Well, no, you shouldn't have been there at all. But that aside, you should have listened to me—just once, you should have listened—and left Donna to my care, so I could remove the offending element without risking her life."

"You mean remove her memories," the Doctor replies. "Not just the ones she inherited from me. A huge chunk of hers as well."

Rose barks out a short laugh in disbelief. "You've got to be joking."

The Doctor shakes his head. "Everything she's seen, everything she's done, everything she's become during our time together, it would all have to go."

"Either that, or she dies," says the original Doctor, taping the IV tube to Donna's arm with perhaps a little more force than is necessary, though there's no chance Donna can feel it right now. "Human minds aren't built to store Time Lord memories. There's nothing else to it. It's a rubbish decision, but someone's got to make it."

"And that someone's always you," Rose replies bitterly.

The Doctor watches as his original self ignores Rose in favor of tidying up his materials, gathering antiseptic and medical tape and stray cotton balls onto a tray. A muscle twinges in his cheek and suddenly the Doctor can foresee just how quickly this conversation is going to speed downhill, careening on rickety wheels until it smashes into a ravine down below. He doesn't need his dwindling time-sense to predict that.

"Well, I guess it's some comfort that I'm not the only one you make life-altering decisions for," Rose says under her breath.

The original Doctor rips off his medical gloves and throws them to the floor with a smack. "Maybe if you lot made better choices, I wouldn't have to make them for you."

"Right. So tell me, do you do this for all the important people in your life, or is it just the women you want to control?"

"I'm not the villain here," the Doctor snaps, fixing Rose with a sharp glare. "And it's wildly unfair to paint me as such. And it's that sort of unyielding, myopic, ridiculously narrow-sighted tendency that renders you unable to accept that some things are just impossible, that blinds you so that you can't see any of the surrounding forest for one small tree, that utterly strips you of the capability to process even the simplest—"

"You have no idea what I'm capable of!" Rose shouts, and the Doctor watches as she furiously blinks back tears, refusing to let them wet her cheeks. The other Doctor's eyes widen in surprise, but Rose pushes on. "You don't know, because you never asked. Did it even occur to you just how long it took me to get back, how hard I fought, everything I had to do? No, you don't know anything about it, you're just sitting there, just thinking, That's Rose Tyler, just the way I left her. But that's not me, Doctor. That isn't who I am, not anymore."

Gasping for breath, Rose combs her fingers through her hair, eyes clenching shut. "I'm not just some broken-hearted, addle-brained human child, I'm not just some unsophisticated ape who's too stupid to consider things like consequences, and I'm not interested in the word impossible anymore. It sort of loses its meaning after you've seen the end of everything, after you've jumped from one universe to another to another to another, after you've seen dozens of other worlds and still, none of them is yours, none of them is what you're looking for, no matter what you do, no matter how hard you try but you can't stop, you can't and you won't. You stop caring about impossible after you've seen the stars go out and come right back, after you've witnessed humanity at its very worst and utter best all in the same damn day—after you've stopped a soldier from dying on the battlefield even after your team is telling you it's useless, she's good as gone, just leave her.

"And then—" Rose says, her voice shaking, lips twisting with the effort of damming back emotions that the Doctor suspects she hasn't let loose for a long, long time now, "—then you watch the man you love more than anything die, right in front of you. Twice."

His original self looks away. But the Doctor doesn't; he's frozen, torn between the intense desire to run off and the burning need to cross the room and envelope Rose in his arms until he's crushed away the memories of everything that ever hurt her. He can feel her pain like it's his own, aching in his chest and stinging in his throat.

(Is this what it means to share a heart with Donna? Compassion ramped up exponentially, emotions absorbed like a sponge, empathy flying off the charts and breaking the meters until mercury spills on the floor and poisons everyone in its proximity? Or is this just what it means to be human?)

"Then," Rose says quietly, "after all that, after he comes back to life and everything you worked for is so close you can almost touch it, you've practically got it in your hands—after all that, he says no." She bites her lip to stop it from quivering. "Well, I say too bad."

She falls silent, mouth pursed in a thin line. Shut tight like a trap so nothing else can escape.

(The quiet in the room is deafening; even the bleat of Donna's pulse isn't enough to cut through the sense of suffocation.)

Scrubbing a hand over his face, the original Doctor heaves a sigh. The Doctor swears the lines around his counterpart's eyes have deepened in these last few minutes; in this moment, he looks every single one of his 900+ years.

"It was never an option, you staying," he hears his original self say. "I'm sorry, Rose. There's no place for you here."

The Doctor feels sick at the words, and wonders if he's ever hated himself as much as he does right now.

Rose's eyelashes flutter once, twice, like her physiology is struggling against everything her ears just took in. But soon her features compose themselves, settling coolly into a perfectly neutral mask. Her face betrays nothing. Even her eyes have gone blank. It's like looking at a smaller, blonder version of his ninth self, even down to the leather jacket. Battle-weary, cold, broken and willing to do anything, anything, to pull himself back together.

(Except he had Rose to pick up the pieces, stitch them up into a shape resembling a person once again. Surely it's the least he can do, to repay the favor. He's struck with the realization of just how badly he wants to.)

Wordlessly, Rose stalks past the two Doctors, leaving the medbay without so much as a glance behind.

Funny, the Doctor thinks. She's only been back for a day, and already, the room feels empty without her in it.

"Don't."

The Doctor frowns at his original self. "Don't what? I didn't do anything."

"You didn't have to." The original Doctor taps the side of his head. "I already know."

"Well, someone's got to talk to her."

"What's the point? She won't understand."

The Doctor watches the doorway where Rose vanished, as if maybe, if he looks hard enough, she'll walk back through it. "Probably not," he concedes. "But still—she's right to be angry."

His original self pushes back from Donna and the examination table, rifling through the medbay cabinets and drawers until he finds what he's looking for—a medical transceiver. "Is she?" he asks, slapping the device on Donna's wrist. "If she really knew what was best for her—"

"Best for her, or best for you?"

The original Doctor glares at him. The Doctor taps the side of his head.

I already know.

Shoulders slumping, his original self returns his attentions to Donna. "I've still got a lot of tests to run here," he says, voice clipped. "And I think it would be best if I did it alone."

Already the Doctor is on his way out.