The Doctor supposed he should have expected this. He lived though it the first time after all, had tried to put a stop to it the first time.

But he hadn't paid as much of an attention to the date as he perhaps should have...and why would he? He could count the amount of times he'd had to do that in centuries on one hand! When was his birthday? No idea! Missy had a better knack at keeping track of that and she...

...speaking of, she was actually the cause of this particular problem he was having right now.

Or rather, her prior, more blonde incarnation.

Who all of his students had abruptly started turning into mid-lecture.

So it was that day, was it?

Not the first time he'd had his day interrupted by one of Missy's prior schemes but this one was particularly grating, with it's interrupting of one of his lectures- on quantum folds and mice this time- and direct impact on the students of which he had a duty of care.

But there was nothing he could do about it right now, without disrupting the timeline of a younger, more Bambi-like him.

So he supposed he better-

It was then he realised that the transformation of his students was just about done and things would likely get complicated very quickly if the Master Lites noticed him unchanged, so he paused that train of thought to do his best to vacate the room before they noticed just that.

Now, back to what he was thinking.

-He supposed he better go to the vault as per usual to ride it out. No need to go looking for Nardole, he would probably pop up somewhere along the way. He seemed to have a habit of doing that, particularly whenever he suspected that the Doctor might be considering doing something remotely fun.

Surprisingly enough Nardole did not manifest while the Doctor tried sneaking down to the vault. Not that he was particularly concerned: he wouldn't have gone far and was bound to show sooner or later.

As for the sneaking itself...it wasn't without incident. He'd nearly been caught thrice, once by a "Master" in a blue dress and twice by ones who looked to be former security staff.

Thankfully most copies seemed to be pre-occupied with declaring themselves to be the Master in typical Master-esque over-dramatics than engaging in any also typical cunning.

Had that been the case, then the sneaking might have been mildly challenging.

He did of course also almost fall down the stairs leading to the vault but nobody witnessed that so he decided, as he went through the motions to unlock the vault, that it therefore technically didn't happen.

"Did you trip? I heard you trip."

The first words he was greeted by when the door opened, Missy sat on a chair and not even turning to face him as he entered.

"No. I did not trip!" The Doctor gruffly retorted as the door closed behind him.

"Ooh, somebody's in a bad mood, I can tell. What's wrong?" Missy partially looked around at that, putting on her best pouty face.

"Oh come on, I'm bored! Spill the beans!" Arms on top of chair, chin on top of arms and Missy's full gaze and attention now resting upon her oldest friend.

"Well, alright then: You. I'm teaching a class and then all of my students start changing from them to you. It's actually quite irritating." He responded gesturing towards her

"Ah, that scheme! You not enjoying everyone looking like little old and yet ever so handsome me? Have any of them got any better dresses?" She was clearly enjoying herself but stopped when she noticed the Doctor's face at what she was saying. "But I'm remorseful, so very remorseful. It won't happen again, I promise. Turning an entire planet of innocent people into me."

"Yes, well, that would be much appreciated." The Doctor conceded as he pulled up a chair next to her to sit down. His darting glances to the vault door did not escape Missy's notice.

"You want to see it, don't you?"

"What?"

"Gallifrey!" And with that she was off her chair. "The crown jewel of the universe! You want to see it when it comes to Earth's sky."

He wasn't to be honest quite sure if he did or not, for a variety of complicated reasons, least of all the reason why he knew his home planet by birth would soon be in the sky of his adopted one.

"Well, it won't be here for a bit yet, now will it? We'll need some way to pass our time." Missy continued, a smirk slowly appearing on her face as an idea clearly grew in her mind. "So how about a dance?" A curtesy and an arm extended. "Someone won't get me a piano, so I've been practicing."

"I-" The Doctor stared at the outstretched hand. He wasn't naïve enough to believe for one second that she would let him have unlimited access to her mind, even now as they worked for her to reform she valued and he respected her privacy too much for that to happen, but for a species with the capacity for touch telepathy...an offered, outstretched and willingly uncovered hand meant a lot more to them than it would have to any human.

So he took it, and in an instant was yanked out of the chair as Missy started leading them into a dance to an imaginary beat. The Doctor was getting a distinct impression with this particular dance being clearly meant for partners, that Missy's decision to ask him to participate wasn't as spontaneous as she'd been framing it.

He was, however, correct in that access to her mind was as firmly barred as always.

"You know why I've not gotten you your piano yet. I don't want to give you something that could be turned into a weapon. Perhaps in a few more years."

"Aw. But imagine if we could do this with a bit more of a beat!"

Perhaps the Doctor might have quipped back that who would be playing the piano if the two were both dancing, when the smaller woman abruptly twirled him and before he knew it he was in a dip.

And it was with that he resolved: well, two could play at that game. On Darillium he and River had spent plenty of time...

...

...Let's just say he'd had practice dancing with a partner and leave it at that.

So with that, the Doctor allowed himself to get into the motions of the dance.

And, for a moment he could almost forget everything that was wrong about this, about the schemes of her old self happening just outside the door, about how he didn't know how much of that old self was still left over in his old friend even now, no matter how much he hoped-

*bang bang bang*

"Doctor, are you in there? It's me, Nardole! There's Masters everywhere out here!"

And with that the dancing had stopped as abruptly as it begun.

"That'll be your pet then. Well go on, let him in before he starts howling and clawing up the door." Missy snapped, very clearly unhappy with this development.

And the Doctor supposed he had better go let Nardole in.

The moment, after all, was now gone.