"My, my. How the tables have turned." Missy tilted her head back to look up at the containment field generator she'd rigged up, then pursed her lips at her captive. Perfect.
The Doctor glared at her through the transparent barrier - predictably, but then again, that particular face was rather good at glaring, so it wasn't as if it was a bother, being glared at. Missy stretched her lips into a deliberate, too-wide grin.
"I don't suppose you'll let me out," he said eventually, gruffly.
"Don't be gauche," she snapped. "We don't ask for that, remember? That's not how this goes. Now be a good boy, why don't you?"
"There's a first," the Doctor snapped, "you telling me to be good."
Missy laughed, delighted. Oh, it was such a shame that she couldn't let him out. He'd be such fun, like this, with his thoughts twisted by that clever little machine.
Missy had had to get rid of its creators, of course. Someone who knew how to affect a Time Lord's mind, in such a profound way? Much too dangerous to keep around. Indeed, the little gadget was almost clever enough to have been invented by her.
And yes, that galled.
The Doctor leaned forward. "You don't want me to be good, anyway. You never wanted me to be." He scoffed. "Good's such a pointless concept, anyway - where's the fun in it?"
He wasn't wrong.
For a moment, she hesitated. She could almost see it - the glory, the destruction, the sheer delight. It would be beautiful. But not, unfortunately, sustainable.
Once, just once, though, just for the hell of it? This, after all, would still be here. Time was such a lovely thing, when you knew how to bend it. She could play with him, then catch him again, undo it all later. After some proper fun.
Alas, the Doctor was too good at running.
The Doctor was too smart: almost her equal. He'd defeated her ploys too many times before. If she let him out, there was no guarantee she'd get him in again. And yes, that was half the fun, usually - not knowing where they'd end up. But that was when he was fully himself. She'd love to play with him some more, like this, but the one she wanted to keep, in the end, was the real him.
No more games today, then. Not of that kind, anyway.
"First time for everything," Missy said lightly. "Shall I give you a piano? Or would you prefer a guitar?"
He grimaced, his eyes flickering along the borders of the containment field, and she could see nervous energy building. Every minute now he'd start pacing. He was only holding back because of her. Because he was putting up a front, as if she'd fall for that. As if she didn't know his restlessness, better than anyone.
Still, he'd stayed with the Vault for her, mostly. Hadn't taken too many secret trips that she wasn't supposed to know about, that his eggheaded friend wasn't supposed to discover. He'd stayed because she had to stay. And because he was staying, so was she. (Really, she could have broken out; the quantum vault wasn't that good.)
Nice circular reasoning, she acknowledged to herself. Aren't we fun, trying so hard?
What a twist, now. He'd meant to test her - take her into a crisis, see how she'd act. Just the two of them, and all right, she'd teased him a little, but then -
Before the Vault, oh, what she'd have given to have him like this! She'd have let him run wild, let him destroy himself - and then, only then, she'd have brought him back to himself, to horrified awareness of what he'd done. Perfection: to force him to acknowledge all the ways the difference between them was a thin, thin line that he was already constantly toeing.
It would still be fun now. But it wouldn't really be him crossing lines, would it? The best satisfaction of the game was denied to her anyway, so why bother?
And besides, if she let him out, that would be the end of it. It would be over, then, everything they'd tried with the Vault, the years they'd spent together. Whenever he came back to himself, they'd be enemies again.
I want my friend back, she'd said. That was how it had started.
Inside the containment field, just as she'd predicted, the Doctor started pacing. Up and down and around, turn and return, a dance of nerves and impatience. Not looking at her, not talking to her, because even like this he knew better than to think she'd let him go. Not so quickly, oh no. Not even if she were planning to eventually.
Looking at him now, like this, himself but not, damn it, she still wanted her friend back.
She could keep him like this instead, keep him trapped, play with him a little. He'd accept that from her, quid pro quo, prison for prison, so long as she kept him from doing damage.
He'd try to trick her, of course. Would spin his game as well as she had ever spun hers, and it would almost work on her, like it had almost worked on him, often enough - but never quite, because in the end, they both knew each other too well.
Missy sighed. She could see it coming, a timeline stretching out before her plain as day. All of a sudden the whole thing seemed incredibly tedious, their old game a tired turn of the same gears in the same tired rotation, a thing entirely lacking in thrill.
"We can't have that," she muttered to herself, and the Doctor spun around inside his cage, eyes narrowed, focused on her. Honing in on what might be a weakness.
Tough luck, Doctor. Not today.
Missy reached out for the controls, and flipped a switch.