Author's note: I've written this months ago and had actually planned to write some more losely connected shots for this before posting, but I haven't gotten around to it so I figured, what the hell, might as well post it regardless. It's a standalone, anyway. Title, of course, from the poem "To His Coy Mistress" by Andrew Marvell, because I'm obviously a terribly original person when it comes to titles.

In Thy Marble Vault

The Vault was empty. It was meant to host a dead body, of course, and those tended to have little need for pretty decorations, or even basic amenities like a bed, or a bathroom. All that was for the living, as were even the flowers and pretty headstones and candles on the graveyards, or the ceremonial funerals and places of remembrance of those peoples who didn't bury their dead.

The Doctor looked at the small figure lying prone on the Vault floor, where he'd had to put her down due to the lack of options, and tried not to think that she looked like a corpse. She was breathing, she was, he had personally seen to it that she would continue to do so, even if she wasn't supposed to.

(Who were they, anyway, to sentence her to death, to think they were the ones who would have the right to execute her? What did they know of anything?)

The Doctor sat on the floor, and stood, and paced, and leaned against the wall, and checked, again and again, that the soft up and down that meant breath was still there, and every time he blinked was another image of another funeral, flames and ash and all the times he'd believed the Master to be dead and gone forever, and he quickly opened his eyes and anxiously knelt to make sure she really was breathing.

A thousand years, they'd said. His mind, unbidden, provided him with the morbid imagery of what her body would look like after that time. But she was alive, he had fiddled with the wires and tweaked a few connections and she was alive. Unconscious, lying on the floor in an empty Vault meant for her empty remains, but alive nonetheless.

He'd had to carry her here. At first he had believed her to merely be feigning unconsciousness, after she had so flippantly wished the perturbed guards a good night, just to get him to carry her. Like a child pretending to have fallen asleep on a long car ride. But then she didn't once let her eyes flutter open, didn't even twitch, and suddenly, she felt very small and frail in his arms, clad in her elaborate skirts like a slightly overgrown dress-up doll. He wondered how she had ended up in that situation, what she had done. What had happened.

She hadn't even tried to run.

A low noise called his attention. Missy was pushing herself to an upright position, one hand braced against the floor, blinking against the dim lights that were provided for some reason.

"Good morning," he quipped, breaking the silence, and immediately felt stupid for doing so.

Her head swivelled towards him so quickly that a human would probably have gotten whiplash. Something undefinable flickered briefly over her face before her expression became guarded, deliberately relaxed. "Oh! My, Doctor, you gave me a start. Were you watching me in my sleep? Because no matter what teenage romance novels might have told you, that's just a little bit creepy. But don't worry, I won't tell anyone."

He watched her pat down the wrinkles in her clothes and try to straighten out her hair, almost succeeding in hiding the wince behind her hands as she did so. "I take it you chased the nasty, nasty executioners away? Congratulations, by the way, you had me there for a moment. I actually thought you'd do it." Her expression was unreadable. He wondered what his own face looked like.

For a moment, he had actually thought he'd do it, too. He hadn't been certain if he could manipulate their machine without them noticing. And then, when he had found a way, for a split second he had considered not doing it. Letting events take their course, leaving the timelines in peace that were already in motion. No one could fault him, and hardly anyone would even know.

He told her that, because he didn't know what else to say, and she rested her unreadable eyes on him until he had to consciously stop himself from twitching.

A hint of a wry smile played around the corners of her mouth. "Where are we?" she asked finally, plainly, glancing at the bare walls, and he pursed his lips.

"The Vault."

At that, her stare flitted back to him, eyes narrowed, head cocked to the side. "Ohh. Sitting in my own grave! Now that's something you don't get to do every day. They did realise, I hope, that their execution didn't quite take? I'd hate for them to believe they succeeded, after all."

"Oh, they know," he assured her. His feet were itching, and finally he got up again and started to pace back and forth, unable to remain sitting for the next bit.. Missy remained where she was, following him with her eyes. Was she staying there, on the floor like a discarded doll with her skirts all around her, in order to unsettle him, or had her execution left her dizzy enough that she didn't trust her balance?

"But I did swear an oath." A beat. "A thousand years, Missy."

The make-up around her eyes was ever so faintly smeared, more so on the left, a bit of blue eyeshadow mixing with the black eyeliner at the corner and hinting in the direction of her temple. Combined with her slightly widened eyes it made her look unnervingly innocent.

"You meant that, then?" she asked, sounding off-hand, as though she should be examining her fingernails at the same time instead of looking at him like that. He nodded, resolute.

"You're actually planning to keep me in here for a millennium?" The doll face lost some of its innocence, like the words had driven it away. Missy sat up straighter and watched him turn fully towards her through narrowed eyes.

The Doctor lifted his arms and let gravity pull them back to his sides, defeated. "What other choice do I have?", he asked plaintively.

She blinked up at him. "You could always just let me go." She didn't sound all too convinced of her own suggestion, her voice about as hopeful as he himself felt just now, but still trying. He shook his head wearily.

"I really can't."

The expected protest never reached his ears, even though he waited longer than should be necessary. Missy seemed to be staring through him now. Beneath her layer of make-up, the Doctor thought he saw a faint trace of shadows under her eyes. His sleeves were being crumpled between his fingers as he looked down at her, and he willed his hands to still.

"You said – you asked me," he said, when it became clear to him that there wouldn't be a response, "to let you live. You said you'd try to be good. You asked me to teach you." He paused, looking everywhere but at her as she sat there, still as a statue, and then he went on quickly because there was no use in delaying it. "Did you mean that?"

Somehow, a tiny sliver of hope had crept into his voice and took root there, against all odds. Silently, he told it to go away. It would only be disappointed.

The sliver of hope refused, pointed out that Missy hadn't yet responded.

The Doctor buried his hands in his pockets so their fidgeting wouldn't be quite so visible, slowly rocked from heels to pads and back again, and waited.

After the carousel that was playing with her thoughts had spun around a few times, Missy averted her eyes.

"I don't know."

The silence that followed felt even worse than the previous one. It pressed down on her aching head, laid itself like a lead blanket over her heavy limbs, numbing them until everything felt as cold and unreal and far away as the artificial lights in this artificial, tiny, bright little world she was trapped in. She shook her head, quickly, and anxious to fend off the oppressive stillness, she spoke again.

"I'm tired."

The silence returned, undaunted by the two soft words. There was nothing else she could chase it away with. Her words, usually so quick to come and form themselves into pretty and witty and cruel shapes, were failing her.

Missy was tired. She had said all that, she knew – she had asked him that. Of course she had, it wasn't like she'd had another choice if she wanted to live. He wouldn't have impeded her execution without the incentive. Would he? No, no, why would he. Even like this, she truly had believed he'd let her die, despite her pleas. A last effort. Anything to save her life, survival instinct still as strong as ever, despite everything. Perhaps she should ask him, ask if he'd have saved her anyway, if he'd have saved her had she laughed and sneered and spat in his face.

She opened her mouth to ask, and then closed it, staring at the wall. Better off not knowing, maybe.

Of course, she could pretend. It was painfully obvious what he hoped for, and it wasn't about fulfilling his oath. It wasn't even about keeping the universe save from her. No, what mattered to the Doctor, the part he had latched onto with his unending supply of foolish, naive hope, was the possibility, however faint, that she would turn good.

Whatever that was supposed to mean.

How could she have meant it, how could she have asked for something when she hardly even comprehended its meaning? Was not killing people good? But the Doctor had killed, and would kill again. He'd been cruel, and demanding, he'd done awful things and made people do awful things and had watched while awful things were happening to people, and he was good. The diffeerence was probably that he beat himself up over it afterwards.

She'd pretend. She knew, mostly, what he wanted to see, and she'd play the role, she was certain she knew how. She'd let him lock her up, let him believe she couldn't get out, and she'd play her latest role in a line of many until she had a new plan, until she once again knew how to go on. It would be easy, almost laughably so.

She was tired. Right now, she didn't have a plan. She had expected to die, and she hadn't fought, and she hadn't tried to run, because she had no plan and nowhere to run to. She hadn't even bothered to make a Confession Dial. And the Doctor had come anyway, and she had begged for help, and now he was waiting for an answer.

"Yes. I did. I did mean it."

Only at his sharp intake of breath did Missy fully realise that she had said that, and for a few seconds, she fiercely wished that she could take it back. She could laugh, she supposed, could laugh at his gullibility and walk right out the door and kick his side to break some ribs on the way out. She could do all of that and more, and still she did nothing.

Right now, she was tired. Perhaps she had meant it. Only one way to find out.

The Doctor was holding out his hand for her to grasp, to help her up, and after a moment she curled her fingers around his and pulled instead, until he relented and sat on the floor with her. Symbolism was a funny thing, she thought, and clamped her lips shut over a giggle a bit too late.

He still hadn't said anything, but his eyes were shining. Missy twitched uncomfortably, pulled her lips back a little in the beginning of a snarl. She could see that he wanted to talk, to discuss all this, but before he had figured out what to say and where to start, she patted his hand and let herself sink back until she was lying on the empty floor.

"Later, Doctor, yes?"

She closed her eyes, hating only for a second how easy it was to do that around him, how she immediately, doubtlessly trusted him not to exploit the vulnerability that came with sleep.

"Later."