Sometimes Yaz felt like her head was exploding. Like when you’re afraid you’ll miss your train and you’re still packing your bags, shaking with adrenaline and hurry, and you end up having to sit on your suitcase just to get it to close, and you’ve stuffed your socks in odd corners, and then you run for your train and when you finally get there, you find you’ve forgotten your hairbrush after all. That was what it felt like, trying to remember the Doctor—not to forget one moment of the things she and Graham and Ryan had done with her, the places they’d been, everything Yaz had learned—and at the same time fill her mind up with everything she could learn about the house TARDIS.
And from it, too. It had taken weeks just to figure out how to access the database, longer than that to persuade the TARDIS to let her access its communication systems. And it had been persuasion, not just hacking. Yaz was beginning to understand why the Doctor had treated her vehicle the way she did. No—no, still treated. Wherever she was out there, that wouldn’t have changed. And Yaz refused to believe she was dead.
She must be the best self-trained TARDIS mechanic in Yorkshire by now, Yaz thought. Maybe even in England. Or, you know, the entire planet.
She couldn’t take off yet—not and be certain of landing again. But she had figured out how to send a personalized distress signal to the Doctor’s TARDIS, and only the Doctor’s TARDIS. Even though she was afraid the Doctor herself was in trouble—why else would she not have come back, unless she couldn’t?—Yaz hoped the TARDIS would be able to come to her aid, even on its own. They did seem to have quite a bit of agency, and what better ally in getting the Doctor out of whatever fix she was in?
It was the moment of truth. Yaz had checked and double-checked the message protocols. She’d thought about inviting Ryan and Graham to join her, but she didn’t want to see the looks of concern on their faces or hear their attempts to save her from disappointment. If she was alone, she could believe it really would work.
Yaz pulled the lever to send the signal.
She hadn’t even taken her hand off the lever when she heard a noise from the street outside. One might have described it as a startling, even a grating noise, but to Yaz it was the most beautiful sound in the world. It was the sound of TARDIS engines.
Heart in her mouth, she ran outside. Her hopes were confirmed as she saw the police box shape of the Doctor’s TARDIS materialize just in front of the house TARDIS.
The door creaked open.
The figure that emerged was blond, colorful, curious and energetic.
Unfortunately, it was also tall, broad, curly-haired and male.
"Are you the one that sent the signal?" he asked as soon as he saw her. He had a posh voice, Yaz noticed in the back of her mind. He sounded like he belonged on the radio.
Still, there was only one person Yaz knew who had that erratic a taste in clothes.
"You’re not Scottish," she said blankly.
She took him into the house, trying to explain as she went. He gave her a sharp look when he realized what the house was, and she wondered if she should’ve gone into his TARDIS instead, but she couldn’t quite face the idea of spending time in the TARDIS when it wasn’t yet her home. There was no doubt in her mind that he was a version of the Doctor. She could tell.
Fortunately, he seemed to believe Yaz’s story, and he confirmed her suspicion that he was an earlier version of the Doctor (he said he had never yet been a woman) despite not being much like the former self the Doctor had occasionally alluded to. He seemed just a little distressed at the idea that his future self might be in danger, when she herself, to her consternation, started to feel tears spilling from her eyes. It had just been so long since she had been able to talk like this with anyone.
"I can tell I have faith in you," said the Doctor. Gently, he put an arm around her shoulders. When she welcomed the touch, he pulled her into his side in a hug, adding, "I’m sure she knows you’re coming for me as fast as you can."
Yaz couldn’t help laughing at the Doctor’s peculiar grammar, and that helped her wipe her eyes and recover her composure.
"But can you help me?" she asked.
"Oh, no, no, no," said the Doctor, and Yaz’s heart sank. "Later self rescues the earlier self, not the other way round. That’s how it’s got to be. It doesn’t seal the loop otherwise; it’s just cheating."
"No," she said suddenly. "Not good enough. You’re the Doctor, right? Then I won’t believe that you can’t find a loophole."
"Is that who I am," he muttered, but it wasn’t a question for her. "You really mean it, don’t you?"
"She’s my best friend and I’m going to find her," Yaz said.
"Oh, my dear," said the Doctor quietly. "I can be stubborn too—"
"I’m aware," said Yaz.
"—but," he said, “how about some TARDIS technique lessons?"
Yaz smiled. “That’s more like it. Look, I've got a list of questions here...."
They went into the Doctor's TARDIS. Yaz suggested it might be easier for her to learn on the one she'd been living in, but the Doctor hemmed and hawed until Yaz realized he wasn't sure about actually operating any TARDIS but his own, and dropped the subject.
It felt strange, just as she had thought it would, to be in this space that would someday be so dear to her. But at the same time, while she could feel a certain essential TARDIS-ness that persisted over time, the differences startled her as well. She stood, taking in her surroundings—a white room patterned with circles, more like a laboratory or a really old computer than the Doctor's—her Doctor's—glowing crystals and stairs. But the ornate wooden chair sitting randomly by the console did seem like exactly the sort of thing the Doctor would drag in and try to find a place for.
"I must have been the closest of me," the Doctor said, "and that'll be why your signal reached me first. I was in the area, you see, running an errand for a friend." He trailed off, a bit sadly. Yaz could see this was yet another story she wasn't going to be told the beginning of.
"Show me how it all works," she said.
In the days the two of them had together, Yaz felt she learned as much about the Doctor as she did about flying the TARDIS. This was already the person who was her friend. Beyond all the obvious differences, they both loved to talk about their adventures, they both could work for hours on end fueled by nothing but tea and biscuits, and they both tended to get inadvisably enthusiastic about really quite dangerous situations. (If she never heard that bell again, it would be too soon.) And yet, this Doctor somehow seemed less... tense, Yaz thought might be the word. When he'd been explaining arcane space-time mathematics to her for a while, and she was starting to glaze over and/or doubt the reality of physical existence, he would sit down with her and talk about other things—strange and wonderful things, alien things, but still concrete things that made her feel anchored: the strange flowers of Earth millions of years ago, the festivals of the distant future, the food they served at a wonderful little restaurant in the Andromeda galaxy. It was almost as good as getting to travel again.
"What have you done this time?" Yaz called as the TARDIS' warning bell began to toll again. The Doctor scrambled up from the other side of the console, where he'd been on the floor trying to reset some settings, and fussed over one of the screens for a moment. He turned to Yaz with a look of pain and worry.
"This time bubble is ending," he said.
She'd learned enough that she knew exactly what it meant, and for a moment she wished she could say "Time bubble, Doctor?" in confusion, as she once would have. But she knew: the time bubble was the phenomenon caused by the overlapping TARDISes, which allowed her to interact with the past Doctor without interfering with their future meeting. And it was ending. She would have to say goodbye again. She would have to lose the Doctor again.
"How long do we have?" she said practically.
"Not long. Minutes," he said. She was already collecting the papers on which she'd been taking notes. Hands full of index cards, she turned to the Doctor and impulsively hugged him. He returned the hug, gently touching her tense shoulders. She tried to let go of the tension: this version of the Doctor would be fine, he would go on and live his life and eventually turn into her Doctor. He had to. But she would still miss him—his terrible puns, his enthusiastic TARDIS lessons, his faith that she absolutely would be able to help his future self. She resolved not to let him down.
She had to get out of the TARDIS, so the Doctor could leave safely. Better to do it quickly. She made sure she had all her things, then turned towards the too-familiar police box door.
"I'll miss you, Yasmin Khan," said the Doctor, and Yaz looked back, startled. The Doctor smiled sadly, fidgeting with his lapel pin. "I'm looking forward to meeting you again."