"Hand me that spanner, would you?" the Doctor's voice came from his position under the floor of the TARDIS. He had removed some of the grating that served as a floor, and was working on the tangle of wires underneath. Donna was not sure whether it was repairs, or maintenance, or just tinkering, but she passed him the spanner and sat down cross-legged on the floor to watch.
"So, when are you going to teach me how to drive this thing?" Donna asked.
"It's not a thing, it's a she. And what makes you think I'm going to teach you to drive her?" he asked, not looking at her.
"Well, it just seems that if something were to happen to you, it might be helpful if I could at least get us back to Earth, or the proper time, or something."
"There's an emergency program that will return you home if anything happens to me, and you are left alone on the TARDIS for a certain amount of time. Hand me that other thing, there."
"Really?" Donna found that equal parts reassuring and alarming. He had planned for something like that? She passed him the tool he had indicated. "All the same, I could help you pilot. I've seen you racing madly about the console. I'm a fast learner."
He looked at her thoughtfully. "Well, perhaps I could show you a few basic things. Nothing too dangerous."
"Of course." Donna smiled. She would be sure to hold him to that. "So, what other emergency programs do you have?"
"Hmm? Oh, nothing you should worry about."
"Why is that not reassuring?" she asked.
He finished whatever he was doing and climbed up to sit next to Donna, sliding the grating back over where had been working. "Most of them are for specific events, all of which are unlikely."
"Such as?"
"Well, for example, I had to write one in the event I was trapped in 1969."
"That is very specific, indeed," Donna said. "Have you ever been trapped in 1969?"
"Actually, yes. With Martha," he said.
"And?" Donna prompted, when he seemed unwilling to continue.
He sighed. "There were these statues. Well, they looked like statues, but they were really creatures. The Weeping Angels. They feed off of time."
"Off of time?" she asked. She wondered if this story was going to make any sense at all.
"Yes. If they touch you, they send you back in time, and can feed off of the energy of your future that never would happen. One minute you're here, next minute you're somewhere in the past, trapped."
"And they sent you to 1969?"
"Yes, with Martha. They can't move if someone is looking at them, so you are safe as long as you don't blink or turn your back on them. I blinked, and we ended up in 1969, without the TARDIS."
Donna gasped. She hadn't been with him very long, but she already had a niggling fear of being left without the ship. "How long were you there? What happened?"
"Months. Martha had to get a job in a shop to support us while we waited for the plan to come together to get the TARDIS back."
"Plan?" Donna asked, unsure where to start.
"Yes. Someone had given me the information we needed to have with us ahead of time. It was…complicated. But in the end it worked, and the TARDIS was sent back to us by a lovely young lady named Sally Sparrow. Oh, we should look her up!"
Donna wouldn't be distracted. "So what did you do for those months while you were trapped?"
"Well, Martha got a job, we got a flat, and I tinkered with building the equipment we needed."
"You had a flat. With Martha. In 1969." No wonder the poor dear had gotten mixed signals from him.
"Yeah. I could have handled that better," he said, as if reading her mind. "She was so brave, so loyal." She wondered what she would have done if she had been in Martha's place. Setting up housekeeping with the Doctor, who was probably going mad wondering if he would see the TARDIS again. Trapped out of time. Would she have fallen in love with him? Fallen in love with the idea of a regular life? She thought not, not under those circumstances. She didn't want a flat and a normal life. She wanted this: travelling with him in the TARDIS, never knowing what would greet them outside the door.
The Doctor stood, holding out his hand to help her up. "Now, about the driving lessons."