Previously: The console room was shrinking.
John seemed to notice at the same time that she did. "Doctor, maybe it's my imagination, but I the console room seems to be shrinking."
"It is," the Doctor said, her mind racing. They reached for each other's hand at the same time.
"Maybe we should get out of here," John said. "In case it keeps shrinking and squishes us."
"Have you been watching Star Wars?"
"Maybe."
The Doctor came to the conclusion that John had a valid point, and that being squished by a shrinking console room would definitely kill both of them. With a tug of her hand they're both off at a run towards the hallway leading out of the console room, John having to hop a little strangely as he was barefoot on the grating.
The hallway had no doors along the walls. Usually the TARDIS brought the doors that they needed to them when they were in a rush, but apparently that habit was being overridden by whatever was controlling the TARDIS.
"Where are the doors?" John asked from beside her. The Doctor had never explained how many aspects of the TARDIS's operation worked. She was about to start talking to stall while she tried to think of a solution, of a way to get control of the TARDIS away from whatever had taken it over, but when she turned her head to look at John she noticed something out of the corner of her eye.
Behind them she could still see part of the control room (which was still shrinking, she noted), but the view of it was getting ever-so-slightly narrower.
The hallway was shrinking as well – it was less noticeable than the shrinking of the console room, but she could still see it. John may not have noticed yet, she thinks, as it was still very subtle. But, she realized with a start, the speed could pick up at any moment.
Without even thinking she started to run again, John tripping slightly behind her, having not expected her to start moving right away. "Doct-"
"Not to scare you or anything John, but the hallway's shrinking too," the Doctor said, cutting him off.
"Oh. Well. What's the plan, then?" he asked from beside her, in step with her now.
"I'm working on it," she said, and she pulled them around a corner into a hallway that was slightly wider than the one they were in, but even before they entered it she could see that it was shrinking as well.
"Why aren't there any doors?" John asked again, since she hadn't answered him the first time.
"The TARDIS can move them around," she said as her mind raced, trying to come up with a fact that would spark a plan. "She usually moves the doors we need to wherever we are-"
"How?"
"Quad-dimensional rearrangement," she answered before continuing. "Whatever's controlling the TARDIS must have control over the location of all the rooms as well and is hiding them." They slowed slightly as they came to a four-way junction. She analyzed the width and rate of change of all the hallways and pulled them straight through, remaining in the path of the one they were in.
"So TARDISs don't have default layouts?" John asked, and she could tell that he was starting to feel out of breath. Her respiratory bypass hadn't kicked in yet, but she knew that it was only a matter of time. They wouldn't be able to keep going forever.
"No, the layout is generally influenced by the TARDIS's – and their Time Lord or Lady's – preferences."
"So there's no default? Nothing the TARDIS can't change?"
Default.
Default.
Default.
Default.
Zero.
They had just turned a corner, but she pulled them back the way they had come and pulled him through the hallway they had just passed. It was a fair bit narrower – they couldn't run side by side, but they kept their hands joined, John's stretched in front of him and the Doctor's out behind her – but she had a destination in mind this time.
"Doctor?"
"There is one room the TARDIS can't change, we're heading towards it now. Not far."
The hallway was shrinking faster than the others, but the turn off was just ahead of them. They squeezed into the next hallway which was blessedly wider; if they were walking they'd be able to walk side by side. It was shrinking fast, though. Maybe it had picked up on her plan, but it would have to be insanely powerful to do anything to their destination.
They entered an old area of the TARDIS, the walls still the plain off-white colour that some of her earlier forms preferred. She hadn't been in this section since then, so the TARDIS hadn't taken the time to align it with the current scheme. She didn't dwell on it, they had hit a slight curve in the corridor and she knew they were close.
The walls were closing in on them faster, but she could see the doorway just ahead. A thought came up that she didn't know if there was a lock on the door, but she was running sideways now and once they reached it she pushed her back against it and it swung open behind her, and she pulled John in with her. Before the door closed she saw that the hallway pulled back to its original width, but there was no way they were going back out there without a plan.