Clara looked up at her Doctor. "Any idea who that voice in the ceiling belonged to?"
"An idea, yes, but it's rather imp- Sorry. I really need to remove that word from my vocabulary, don't I?"
"So," Clara continued, "who is this person whose presence is extremely highly improbable, but just short of impossible? Because I'm the only impossible person allowed in your life."
"Yes, you are," he replied, smiling just a bit for her, as she'd intended. "From your description, it sounds almost like Rassilon, which really shouldn't be possible."
"Except that he's managed to get loose once before," the other Doctor offered, coming over with Rose to join the discussion.
"Yes, but that was a rather extraordinary circumstance."
"And this isn't?"
"Point taken, but it feels different."
"And neither one of you has any idea where we actually are?" Rose asked.
"No," her Doctor replied. "I'm not even convinced that this is a real place."
"I think I know where we are," Clara interjected.
"And where's that?" her Doctor asked curiously.
"I think we're inside your head, somehow."
"That's ridiculous!" he scoffed, just a little too quickly and too rudely.
"Not necessarily," the other Doctor said thoughtfully. "Why do you think that, Clara?"
"Because everything here is him…you…oh, this is so confusing!"
"Don't fuss over your grammar right now. I think you're on to something. Keep going. Why do you think we're inside my head?"
"Everything in here is about you. You're the tenth Doctor, his most recent past existence. Rose is one of the most important people in his entire life."
"So are you. You've been with us since the very beginning."
"Yes, yes, that's all very interesting, but how would Rassilon get inside my head?" Clara's Doctor said rather petulantly.
"Maybe he's not really, properly real," Clara mused. "The things he said, it was almost as if he was a…a representation of all the reasons you ran away from home in the first place."
"That is brilliant!" Rose's Doctor enthused.
"No, it's not!"
"Why're you being so pig-headed about this idea?" Rose demanded, stung by the Doctor's behavior towards Clara. "Where do you think we are, Doctor?"
"Certainly not inside my own head!"
"What are you so afraid of?" his counterpart asked wisely.
"It's because that other Doctor is here, too," Clara stated. "The one you tried so hard to forget."
"He has no right to that name!" her Doctor exclaimed wildly. "He gave that up a long time ago, when he went against everything I've ever stood for. He's not the Doctor."
Clara's eyes were drowning with infinite sorrow as she reached out to take both his hands. "But he is you."