:/:
Silence was an almost extraterrestrial force, one of crystalline nothingness which hung in the air like a thick fog that choked the words lingering in the throat. Silence was an unavoidable nothingness. A quiet that was deafening. Silence was the void; broken by noise which shattered it like glass. The lack of life to break the deafness with ragged breaths and the beating of two hearts. Silence was noise, but quite unlike one she eas accustomed too. It was the deafening lack of noise that was noise, the loudest of noises one could hear, as they're no other competing sounds to disperse what is perceived as silence. True silence, so The Doctor said, is golden. And though this may be true; silence is also lonely, a constant companion nonetheless of your innermost thoughts. The sound of silence is not the lack of noise; but the misinterpretation, the misconception of what is sound. And it now hummed in the Vault.

Unbroken silence. And a broken Time Lady to experience it.

"Miss-y", said a sing-song voice, echoing in her subconscious. "Thinking of giving up yet"

"No", she brushed it off bluntly.

"Oh, come on. You can't tear the evil out of you just like that, now can you. It's a living, breathing disease that has grown through you and controlled every move you have made until now. Think of the consequences: who will you be without evil? If there is anything left of you to be something". 

"You aren't real. You're just my psyche, trying to confuse me and make me doubt myself".

"Oh, I'm real alright. And I'm you. From your past", he started and then changed his tone to one that was slightly more aggressive. "I'm here to change your mind. Because, you have admit, this isn't us. I never put us down as the committal type, let alone a confined one".

Missy didn't know what to feel. Anger, sadness, who knew? But she felt a change, a shiver, something up her spine.

She didn't know what was wrong with her. When her symptoms began, it felt like an almost dead feeling, just emptiness. Then it hit. Her skin started to burn; her blood turned to knives that cut at her as it flowed through her system. It was like he had said, she was tearing a part of herself out and now it was rebelling. Refusing to budge. If she was to get rid of her evilness well, put simply, she would go with it too. Whatever was left afterwards would just have to be picked up and stitched back together. That's if she actually got there. She could feel an impending regeneration itch under her skin.

"I can't be like you again", she murmured, slurring her words. "I can't go back to being you".

"Then you'll have to withstand Hell".

"I've been though Hell too many times to count, on too many worlds. To die good, without hope, without witness, without reward, that is no Hell to me".

"Hm" the Master scoffed and quietened. "We'll see then". And upon that moment, though she had made peace with destruction, it was almost like Death's sullen face had taken her by the throat and threw her to the ground. Curling herself up into a ball on the floor, she resigned to sweating and swearing herself to death. On the cusp of a seizure, her muscles jerked in symphony with her erratic heartbeat.

"He... Help", she mumbled in as loud a voice as she could muster before her eyes rolled back into her skull...

:/:

When Missy woke, she couldn't quite remember, well anything. Nothing but knives. Hundreds of them with their handles pointing towards her in her subconscious. And most frightening of all was that, no matter how much he tried, she couldn't open her eyes. She just couldn't muster up the energy.

"Just let me die", she mumbled. "I can't go on like this". Forcing her eyes open, she was surprised to see that the four walls around her had fallen to become endless miles of red smoke and fire. It was practically pitch-black, a forgotten sun killed by the thick cloud that suffocated its light. She blinked and found herself stood up, staring into the apocalyptic wasteland in from of her.

"Is it her? Is it the new Queen of Gallifrey?" announced a familiar voice behind her. She turned and saw a figure silhouetted against the orange light, who took a step forward to reveal himself. It was The Doctor, garmented in layers of clothing covered in bullet holes and with a gun at his side. His sonic screwdriver, the tool he used to secure peace throughout the galaxy, was nowhere to be seen. But that wasn't the most worrying subject. It was his eyes. Once with ice blue irises like crystals were now pale and unblinking. A white film covered them, making it seem that he had no irises or pupils at all, just ivory pools.

"Theta, your eyes?!" Missy exclaimed and The Doctor rushed forward and held her head in his hands.

"Oh, they see everything. They see you leading us gloriously to Hell". He cocked his head, as if he could sense something, then continued to gaze at Missy with blinded eyes.

"We are all dead, can you not see?" he continued, a grimace appearing across his face. Missy could only look on in horror as she felt her hand grip something. "You're a killer. See where your power leads". Lifting her empty hand up, she gasped fearfully as she saw it was slick with blood and looked down to see she held a knife. A knife that was deeply rooted in The Doctor's abdomen. "I trusted you", he said, in a raspy voice, as Missy pulled out the knife and threw it away in disgust. Putting her arms around him, she lowered him to the ground and held her head.

"You're not real. This isn't real. I'm hallucinating". Standing away from Theta, she attempted to slow down her breathing to no prevail, only managing to just stop herself from hyperventilating. "You're not my Theta!" she shouted at the dying Time Lord in question. But even if it wasn't her Theta, it didn't stop her from throwing herself at him, wrapping her arms around his chest and listening to his fading heartbeat.

Slipping into another bout of unconsciousness, all she could mutter was expletives under her breath until the red smoke cleared to become the empty Vault again. The Doctor's corpse disappeared from beneath her, leaving her curled up on the Vault floor, clinging to nothing but silence.

:/:

"No interference here, as far as I can see. The vault's secure", The Doctor murmured to himself, half alert to Bill's growing realisation about the TARDIS, half alert to the eerie silence within the Vault.

"So your box can move? It can go anywhere it likes?"

"Mmm. Good, innit?" Nardole commented, noticing The Doctor's frown.

"Anywhere at all, in the whole university?" Bill asked naively. The Doctor scanned the door with increasing urgency. Missy wasn't usually this quiet. He occasionally had a suave 'Come in' ring through the doors, but most of the time it was just expletives. Perhaps he was too late, perhaps this water-monster-puddle-thing, Heather, had already taken her. But why? Missy seemed completely serious about this whole 'becoming good', so why would Heather latch onto her?
But his wild thought had been proved wrong as the sonic screwdriver hummed softly to prove that the biometric print of a Miss. Koschei Oakdown did still reside in the Vault.

"Is it my imagination, or is this taking longer than normal?"

Peeking her head back inside the TARDIS, a wave of realisation rushed over her. "Hang on. The room's still inside the box. This isn't a knockthrough", she muttered, trying to figure out the puzzle.

"No".

"Doctor! lt's bigger on the inside than it is on the outside!"

"Way-hey! We got there!" Nardole laughed and shook hands with The Doctor excitedly.

"How is that possible? How do you do that?" Bill enquired. Ah, more questions. This one was a curious one, The Doctor had to admire that.

"Well, first you have to imagine a very big box fitting inside a very small box", Nardole attempted to explain, but to no prevail. 

"Okay", Bill answered, still completely confused.

"Then you have to make one. It's the second part people normally get stuck on".

"Can we shut up, please?" The Doctor retorted. Humans. Always busy asking questions and spending too long trying to answer them. Just don't ask the questions in the first place. "Busy, busy. I need to know if there's any interest in what's inside this vault". 

"Why, what's inside it?"

"Something I don't want anyone being too curious about".

"So you put it in the middle of a university?"

"Ooo, valid point. Yeah, nice", Nardole commented and The Doctor turned around away from the Vault doors.

"Either the creature came here specifically for what's in here, or it's just a coincidence", he pronounced, trying to attach to Missy's mind at the moment. Even though it was like grasping at straws, and it felt like he was more likely fixing Missy's mind then communicating with it, he was relieved to actually find that it still was thinking and... Dreaming. She was asleep, he hoped.

"It's just a coincidence", Bill replied quickly.

"Well, we can't know that for sure".

"Yeah, we can. It was here for ages before it did anything. If it had work to do, why would it lie around in a puddle?" Hm, curious and had common sense.

"I don't know. Maybe it’s a student?" The Doctor quipped, trying to brush off the fact that he had been beaten by a twenty year old human.

"Oh, banter. It's good, this. Your go again", Nardole laughed, but his chuckles soon turned to horror as the sound of water flowing down the steps echoed around the university basement. Heather was here.

"Nardole, we need to move away from the doors and towards the TARDIS", The Doctor whispered and watched as  the water stopped for a moment and Heather materialised from the puddle, unblinking eyes glaring at the three.

"What if it attacks us?" Nardole asked, in a quiet a voice as he could muster without erroring. 

"Well, that's the good news. It means it's not interested in what's inside the vault. It just wants to kill us", The Doctor answers and quickly compiled a telepathic message to Missy. 'I'll be back', it said and he hoped that perhaps she wouldn't chew him out too much for being late.

"Oh", Nardole mumbled

"Run!" The Doctor shouted, turning on his heels and escaping into the TARDIS.

:/:
:/:

When The Doctor found Missy, an age later, he had been the one to swear. His hands had been cool on her forehead as he murmured her name, but she could hardly form a coherent thought, much less anything provocative or smutty about the situation at hand. She understood it by then of course. Realised what was missing from her blood, what no longer ran through her veins.

"Missy?" he said in a whisper, rolling her onto her back and unbuttoning the collar of her blouse so that she could catch her breath. "Missy, this is... What the hell have I done?"

"I saw you die" she rasped, blinking hard to attempt to focus on his face. "I had your blood on my hands and I couldn't do anything about it. I don't want to see that again, Theta. Let me die. Please. I'm begging you. Just let me..."

"No," he whispered, his voice cracked, thinking about what to do. She had pushed herself too far. Or perhaps he had, that was his fear. Missy had taken something out of her system. Something that she relied on and couldn't function without. "I'll be back, OK? I'll be back with something to help."

"No," she repeated, reaching for him, but he was already gone.

:/:

"We're different to humans, you and me", The Doctor murmured, waking Missy from her slumber. "We don't need these chemical responses they elicit when they do something good or bad. Puts a spring in their step, makes them want to do charitable things. For us, it just sits there and does nothing. You know what I mean, don't you?"

"Dopamine", Missy replied, huskily. "It's released when you've achieved something or close to acheiving it. I used to love the feeling of it in my veins when I destroyed a planet. But now I realise, it wasn't a help. It was my drug. My addiction".

"What happened, Missy? What symptoms have you had since I left you?"

"You don't have to take your name quite so literally, Doctor".

"Answer the question. How do you feel?"

"Like shit".

"Can you expand on that?"

"I hallucinated seeing you die. On a different world. You told me that you trusted me, then I stabbed you in the stomach. Can we change the subject?", Missy said swiftly, not liking that she had to relive it again.

"Anything else?"

"I blacked out a few times, heard me in my head, but that's normal. Sweated and cried probably all of my bodily fluids out. But apart from that, I'm fab".

"I don't think 'fab' is the word for it" the Doctor replied, approaching the bed and sitting beside her.

"Then what is it?"

"Dependent. And this is your body reacting to having to stand on its own two feet. It can't take it. But this will help it along for now. It'll take the pain away".

Missy felt a sharp pain in the crook of her arm, and then a blissful coolness spreading through her. She took a deep, shuddering breath, a smile passing over her features, and with that she fell asleep for the first time in days.

She had no idea how long she slept for, but when she woke up, she found that she had been moved to the bed. He was curled up beside her, wide awake and watchful.

"Hey," she breathed, shifting fractionally closer to him and noticing with satisfaction that he didn't edge away. "What did you give me?"

"Synthetic dopamine. Enough to stop the withdrawal symptoms for now, but you might need regular doses of it until your body starts producing it in the right amounts.

"Or until you let me out of here."

"We both know that isn’t going to happen," he said gently. "I'm sorry."

“Don't be," she mumbled, resting her head on his chest and listening to the double beat of his hearts, reassured that they weren't going to fade just yet. "Just... don't leave me."