Everything's going to be okay.
That's what he tells himself, has to tell himself, when he's faced with the ultimatum. He's never seen her look at him this way, with this much heartbreak and the dead eyes of a woman who's given up, who knows she's lost. He's watched the last speck of hope fade from her eyes before him. He's the one who has the power to solve this, just as she's the one who created the problem. It's really quite characteristic of them, unchanging as ever in their roles.
Show me something, Doctor. Anything. Prove to me that at some time in your life you have felt some sort of affection for me, some sort of friendship. Anything.
He supposes that's one of the characteristics of hitting rock bottom – having nothing left to fight for. The Master, well she's always had something. Live, just to spite the Doctor. Come back to life, just to spite the Doctor. Conquer, just to spite the Doctor. Kill, just to spite the Doctor. Die, just to see that look on his face everything he wants is taken from him, just to spite him.
But spite needs reciprocation of some sort. As he stands there with a look of pure indifference on his face, Missy begins to doubt, for the first time in her life, that he cares at all. So she presents him with an ultimatum, a last chance to prove he cares.
This is it, Doctor. I'm done. Say the words and you'll never see me again. Ever. Say the words and I'm gone. Or... you could save me…
One time while visiting Earth, although she'd never admit it, Missy read an Earth story. Even more surprisingly, she became infatuated with the tale. Peter Pan, it was called. As she read of the boy who flew around taking young humans on adventures, she found herself strangely reminded of an old friend. Oh sure, it was fun for a while to imagine what might have happened had the Doctor refused to grow up and lived forever in his childish glory, refusing to give up his childhood (and maybe even his childhood friends). It was comforting even. Then she found a kindred spirit, a fellow jealous, vindictive beauty, both fond of the men who travel the stars. Both prepared to play dirty to get what they want. Like Tinker Bell, she needs applause to live. She has to be noticed, praised (maybe even chastised) but more than anything acknowledged. She demands the attention from those she craves and sulks in a huff when it is not given.
If you've ever felt anything for me, show me.
She'd take a slap across the face, she'd let him clap her in irons and she'd even accept him turning her own weapon on her again. Anything would be better than the look of indifference, the empirical proof that he doesn't care, or so she thinks.
Show me you cared. Show me that at some point our friendship meant something to you. Anything.
The problem is he cares too much. He cares so much that it threatens to consume him, as it has her. He knows what he has to do to save her and more. The act itself would be so small, but the result could tear the universe apart.
He's the Doctor without her, but he doesn't know what he is, who he is, when he's with her. She's the Master through and through, but he has to wonder what she would be without him. They're two friends with a past so intertwined that sometimes it's difficult to separate the concept of each as an individual. He's the second to her first. She might even call him her second, just to tighten her possessive hold on him. He might say she brings out the worst in him, but many would say they flourish when motivated by the other. He'd be lying if he said he would be the man he is today without her.
But he can't do it.
Just say something nice.
He just can't.
So the Doctor does something he's not proud of. He turns his back and walks away to his TARDIS.
The answer is given.
The result is an excruciating pain in his hearts. It's amplified in hers ten times.
The agony is too much so he turns again, but then he has to face the look of utter heartbreak on her face.
He's lost her… almost?
He strides back over to her with the determination and conviction that only his feelings for her could inspire. He takes her cheeks in his hands and pauses for a moment to look for that last speck of hope he knows has to be there. He thinks he's found it. Then he kisses her.
The Doctor knows he can't explain exactly what their twisted relationship means to him with words, but he hopes he's doing an okay job of showing her.
When they pull away, the Mistress is smirking.
The applause rings loud in her head, the spotlights all back on her.
"Don't," he says, meaning to stop her from whatever plan of self-destruction she has created. It is his 'something nice'. Theirs is probably the only relationship in which the word 'don't' is akin to a profession of undying love.
"Oh, Doctor," she replies as if talking to a child. "It's never too late to admit how you feel for me."
But it's a weak retort by her standards, one that's done very little to hide her vulnerability. Not from him. Not when he knows her this well.
As he watches her, he notices a barely detectable hint of her former sadness in her eyes. It makes him wonder if what she said is really true.
He takes her hand, a peace offering, and leads her into his TARDIS, crossing boundaries he has been careful to maintain before.
"All of time and space," he says as he spins around in front of the console. "Where to first?"
It's his classic line, used on so many before – it almost makes her roll her eyes – but she'll take it.
A victorious grin makes its way onto her lips as she steps forward eagerly, trapping him between her and the console.
"Second star to the right," she recites as reaches behind him to flick the dematerialisation lever, pressing even closer to him and capturing his gaze, "and straight on 'til morning."
As she moves in closer, her lips barely a breath away from his, the Doctor stops her, grabbing her hand to still her. It's not a move of distaste; it's a move of concern. He searches her eyes, seeking out the hurt and betrayal he's caught a hint of.
He wonders if perhaps he has crossed a line, pushed her too far. They play their games, dabble in life and death, but they've never given up on each other before. Not completely.
She smiles again. To disguise the pain. To hide just how much he's hurt her, how much he can hurt her. She's drawing him in. Her eyes. Her lips. Her touch.
He relents. It's easier to give in to her. Things aren't as difficult under her touch (oh but they're even more difficult). Her kisses can soothe any lingering tensions between them (and create a thousand more). They're okay for now, she's happy for the time being, though his concerns still plague his mind.
One day it might just be too late for them.