I don't own Doctor Who. All rights go to their respective owners.

Days In The Vault

"I've got to say Doctor, you've had some crazy ideas in the past but this one takes the biscuit." Bill Potts remarks with folded arms.

"What was I supposed to do, Bill?" The Doctor sighs.

"Um? Not this. I mean, a small part of me can tolerate Missy. I mean she still terrifies me, don't get me wrong but I can somewhat tolerate her but. Him? No way. In fact, Doctor, I want to beat the…"

"I can't just let them loose on the rest of the universe. Trust me, this is the most suitable option." The Doctor says in a calm tone as Bill huffs and slumps down in her chair.

"If you three had shown up ten minutes later I would've been a Cyberman thanks to him." She hisses angrily.

"I know. Those two are not spending a thousand years in the vault for nothing." The Doctor reminds her.

"I hope he suffers in there. Actually, Doctor, am I allowed to ask Missy if she can make him suffer?" Bill questions.

"I wouldn't. She'd probably take you up on that offer." The Doctor admits.

"How does it work in there anyway. I mean, the vault was only made for Missy, wasn't it?" Bill frowns.

"They've managed. I've just started getting two of everything for them. Currently I'm working on getting two beds for them so they don't have to remain sharing."

"Wait hold up. They share a bed. Ohh god." Bill says with a shudder.

"What?" The Doctor frowns at her.

"Well, you and I both saw how they were together I mean. I wouldn't want to think…"

"No! No of course not. Missy would never sink that low." The Doctor responds with a similar reaction to Bill's at that thought.

"To be fair, I think Missy would be the type to try anything once." Bill notes.

"Let's just change the subject okay?" The Doctor cuts in sharply.

"What, are you jealous?" Bill smirks at the thought.

"No, of course not. Don't be ridiculous." The Doctor mutters.

"You so are." Bill sniggers before frowning.

"Wait which one are you jealous of. I mean they're the same person…"

"Bill." The Doctor glares at her before glancing down at his psychic paper that had just lit up with various words.

'Don't think I'm being dramatic because I'm not but I want to kill myself.' – The Better Half

Rolling his eyes the Doctor sighs, leaning back in his chair.

"That one of them now?" Bill questions.

"Missy." The Doctor shows her the message.

"Think we should go down there?" Bill queries.

"I think I should go down there." The Doctor corrects her.

"Aww. Please let me come."

"No! They can be dangerous Bill. Very dangerous."

"And what so, you'd rather just go by yourself then. I mean come on, Nardole's out. Please let me come." Bill practically begs.

"Fine. Fine! But you do exactly as I tell you and you can wait outside the door." The Doctor warns her.

"Fine by me." Bill holds up her hands as she follows the Doctor.

"I just want to see Missy deck him one."

The Vault

"OFF!" Missy's voice sounds out angrily.

"No. This is my vault too." The Master retorts angrily.

"That is my piano."

"It's our piano and besides. I'm so much of a better player than you are. I have such a good taste in music."

"Ooh one day you will realize just how god awful your music taste really is believe me. I know. I am you!" The Doctor and Bill here Missy snap just as they approach The Vault together.

"Well at least I don't spend hours on end whining all day and pretending that it's singing. I am the more musically talented than you." The Master retorts.

"Ohh shut up you egotistical wankpot!" Missy yells back as the Doctor and Bill enter the Vault, the Doctor folding his arms as he takes in the sight of the pair.

The Master on the piano and Missy standing up, looking as if she were about to commit murder.

"Doctor, make him get of my piano." Missy whines.

"It's our piano." The Master corrects her.

"Missy was here first." Bill can't help but interject.

"You see?" Missy practically explodes.

"Would the two of you stop acting like children." The Doctor scolds them.

"He is a child." Missy mutters.

"Oh I'm the child now?"

"Yes you are now get off me piano!" Missy commands angrily.

"Do you see what I have to deal with?" The Master looks between the Doctor and Bill.

"Can't believe I'm saying this but, you were a better roommate, my dear." The Master looks to Bill who glares at him.

"That's it. I'm decking him one…"

"Ooh please do. I'll help you."

"Everybody just stop where you are right now!" The Doctor calls loudly in exasperation.

"Ohh come on, Doctor this is ridiculous. Let me return to my time stream you have her. You don't need me. I am her. I can't take another day in this place. I hate this vault. Please let me out. I can't cope." The Master whines as Missy scoffs.

"Ohh pull yourself together you cretinous fuckwit!" Missy snaps.

"Alright, both of you need to calm down and deal with this situation like adults. Now, I know it's not ideal…"

"Not ideal? We have to share the same bed. Not ideal is an understatement." Missy mutters.

"That's not such a bad thing though is it. I mean, we could make it more ideal." The Master gives her a look that makes both Bill and the Doctor want to throw up.

"And I told you that, that was very wrong and not happening." Missy retorts.

"Ohh come on, darling…"

"If you call me 'darling' again I don't care if you're a past version of me I am going to…"

"What both of you are going to do is shut up. Take two sides of the room, leave each other alone for the rest of the day." The Doctor starts.

"I really doubt that's going to work." Bill notes.

"Ohh it will, believe me because if you two." He looks to the Master and Missy.

"Can go the rest of the day without arguing. You will both receive a reward."

The time lady and lord instantly fall silent as the Doctor smiles at the peace and quiet, smiling even wider at Bill when he heads toward the door.

"What?" He glances at Bill who is shaking her head when they exit.

"You're so going to regret saying that when they're asking for really strange stuff."

"That's if they manage to spend the rest of the day not arguing." The Doctor reminds her.

"Yeah, I'm not hopeful." Bill replies and the Doctor has to nod.

"Neither am I."

Later…

"I can't actually believe it. It's been three hours and they haven't argued once." Bill notes, munching on chips as she and the Doctor watch the live security footage they have of Missy and the Master in the Vault.

"They actually seem to be conversing. I'll turn the volume up." The Doctor says, doing so as he and Bill crowd around the small screen.

"Ohh I've had some fun before we got here, you know I met this very, very beautiful woman. She wasn't a time lady. Actually, I don't know what she was but she had her very own Tardis. Ohh I had some fun with her, believe me. I was going to meet up with her again before I crashed my own Tardis." The Master is telling Missy, tilting his head to the side.

"If we are to be stuck here, do tell me what you've been up to."

"You know I shouldn't do that." Missy retorts, looking at her nails.

"Ohh come on, a few fun stories." He pleads.

"Fine. Alright, I had a few problems with my own Tardis at one point and until it was fixed I spent some time being a liaison officer at a hospital. That was, that was interesting. Ohh and because the Doctor had this companion who was a teacher, I thought it would be funny to become the deputy head of one of the schools she ended up working in. Now that was fun, expect the rest of the people I worked with were a bunch of idiots." She notes.

"What friend of yours was that?" Bill looks to the Doctor who has a puzzled look on his face.

"You know, Bill. I. I just can't remember."

"Ahh well, can't blame you for forgetting you are like several thousand years old or something yeah?" Bill tilts her head to the side before offering the Doctor a chip, who accepts it.

Surprised that his method of attempting to get Missy and the Master to stop arguing is almost beginning to work.

The Next Day

"I can't believe it worked." Bill stares as she and the Doctor stand outside The Vault next day, waiting for the doors to open.

The sight they are met with when the doors open causes them both to raise their eyebrows.

Missy, wrapped up in a blanket, on top of her piano.

"We might not be arguing but this is my piano." Missy murmurs, with her eyes closed.

"And she hogs the bed." The Master calls.

"Not saying anything, not saying anything." Missy mutters through gritted teeth.

"It doesn't matter if you do or you don't Missy. You both did as I asked. So you will get a reward." The Doctor says, looking to them both as Missy gets up off the piano, moving to stand by the Master.

"Told you you'd regret this." Bill says in a sing song tone under her breath as the Master and Missy approach them.

"We've made a list…" They both hold out stacks of paper as Bill chuckles to herself, patting the Doctor on the shoulder as she heads toward the exit.

"Told you so."

Thank you all so much for reading this. This is my first FanFiction for Doctor Who, so I hope I haven't done a terrible job of this. I just wanted to write this because a) Missy is my favorite, Michelle Gomez is a legend and b) the season 10 finale killed me. I mean, I knew Michelle Gomez was leaving but I didn't expect it to hurt as much as it did :( I do have some plans to add lots more to this, do comment and tell me if I should carry on. I do accept requests if anyone wants to request anything for this and thanks again for reading :)