"Please stay." Missy's voice was small and pathetic, not all on purpose. "I don't want to be alone." She had her back to the wall of the console room, which really wasn't very comfortable, but it meant nothing was going to sneak up on her. Her neck was aching from having spent the past week looking behind her at every noise, imagined or otherwise.
The Doctor paused, mid-step and turned back to face her best enemy.
"All that time spent alone in the vault." Missy shook her head. "I don't want to go back to the person I was. I want to be on your side." She sniffed and wiped a tear from her cheek with the back of her hand.
It worked just as Missy had hoped, and the Doctor returned to her side, putting an arm around her. It wasn't all manipulation on Missy's part: she really didn't want to be alone with her thoughts. Not when she kept remembering what had happened when she turned her back on her previous self.
"You won't," the Doctor promised, rubbing at the top of Missy's arm. "I won't let you."
Missy smiled at the Doctor and raised a hand to the her cheek. "I know I can always count on you."
"And can I count on you?" The Doctor turned towards Missy. Despite their positions, the Doctor's expression was serious.
Missy nodded. Although she meant it, she knew also knew it was the only answer the Doctor would accept, or Missy would find herself back in that vault. "You're my best friend and I love you." She dropped her voice to a whisper, meaning the Doctor had to lean closer to hear. "I've always loved you." Unlike the last time she'd kissed the Doctor, the first time she'd met his previous self, she made her approach slow, so the Doctor could back away if she wanted. But she didn't.
Their lips met and for the first time in a long time, Missy felt loved.