Word count: 600
Summary: Martha goes for a nap in the TARDIS. Pre-emptive post-ep fic (or perhaps even post-second-ep fic) based on a tiny spoiler I think I have worked out from "Made of Steel".
"Just one trip." That's what they'd said.
And it had been everything she could possibly have imagined, and more. Exhilirating. Fascinating. Astounding. Frightening.
The Doctor had shown her through the TARDIS's cavernous corridors to the bedrooms. It had seemed natural at the time -- she was exhausted. But as she lay there she started to wonder. That had been the "just one trip", hadn't it? He should be taking her home now, shouldn't he? She could sleep in her own bed.
Or this one. This one was good. If anything it looked more comfortable than her one at home.
And she was knackered.
She was asleep all of thirty seconds after tucking herself in.
* * *
Somehow, she knew she was dreaming. It was slightly reassuring to know she could still tell the difference after recent events.
She found herself in an impossible room with an impossible number of walls, that somehow were still all at right angles to each other. And in every wall was a mirror -- or were they windows? -- and behind all of them were people. On the other side of the windows, or looking out from inside the mirrors, depending on how you looked at it.
"What's going on?" she asked the nearest, a blonde girl with big eyes.
"It gets in your head," came the reply. "Don't worry, it freaked me out at first too."
A short girl in a frankly ill-advised glittery catsuit responded, "It's really very simple. Your consciousness is an epiphenomenon of neuronal interactions in your brain. The TARDIS is simply scanning your brain to model those patterns and make some minor alterations. Emulating a simple finite state Turing machine like a human mind is a trivial problem for a non-linear extracomputational entity like the TARDIS."
"She means, it gets in your head," said the blonde.
Martha frowned with confusion (which seemed like a very detailed thing to do in a dream).
"Careful, you're slipping into a recursion error." A dark-haired woman with an imperious tone.
"I still don't understand."
"It's a symbiotic relationship." The latest to chip in had long blonde hair but the same sort of air of authority as the last one. "When you travel in the TARDIS, it becomes a part of you. And you become a part of her."
"It's obvious really," said a redhead with a large earring. "And for some of us it's rather literal."
"I wouldn't be who I am today if she hadn't," said a guy in a leather jacket, shuddering slightly.
"Will I remember any of this?"
"Well, of course you will," said the catsuit girl. "The TARDIS will and so we all will too. But she won't." Martha looked round and somehow she was looking at herself, asleep in her room. Her room? When had it become her room?
"I don't understand."
"You're not you, any more," said a young girl with a long fringe and a stripy shirt. "You're the Ship's model of the Martha Jones entity. She had to make you to make the changes to Martha's brain necessary to allow her to travel in time, understand other languages, that sort of thing."
"So I'm not dreaming this?"
"If anything, this is dreaming you," said the long-haired blonde. "But the process is almost complete now."
Not-Martha felt the vast, powerful consciousness of the Ship rising to embrace her, and all the others in the hall of mirrors, re-integrating this brief linearised diversion into the fractal complexities of the timeship's mind. But as her localised awareness ebbed, she was sure of one thing:
It could never be just one trip.