There’s a knock on his door, and an inquisitive “Adric?”
He’s well aware that it’s the Doctor’s voice; it has to be, by process of elimination if nothing else. But he’s never really seen this other Doctor, except those few moments before —
Just before. He hasn’t been thinking about what came between before and after all that much.
“Are you all right, Adric?”
He’s smaller, for a start. Smaller and younger and more worried somehow, but the weight of ages, at least, seems to have been shed with that absurd scarf of his.
“Can I come in?”
And he’s more persistent and he simply won’t go away and leave him alone. Adric's in no mood at the moment to ignore the spite, the feeling that this strange man had taken the Doctor away.
Romana walked off with K-9 and now the Doctor was dead at the base of a tower and there might as well be no one in the TARDIS but him. Him and the bits of the fabricated world that he can still see around the corners if he isn’t careful; any equation became easier the second or third time you solved it, until you can complete a transfer almost without thinking.
He wants the Doctor back.
“Adric.” He’s stopped asking.
“What?” He doesn’t mean to snap at him, because it wasn’t his fault, but it sounds that way anyway, and Adric doesn’t feel like apologizing.
“I’d like to talk to you.”
He doesn’t answer, but the Doctor walks in anyway. “Are you feeling better?” he asks; his hat is in his hands. “Nyssa’s very worried about you.”
“You know, I think I could do it again.” He isn’t feeling better, not all that much, but it helps to focus on the maths. Because it really was remarkable, what he’d done, drawing up a miniature world, and the Doctor and Romana would have been impressed. They’d know he could have done it on his own too, without —
Without what came between before and after.
“The calculations. Castrovalva. I could do it again. I’ve been working out the formulas. I think I’ve almost got it by now.”
“You won’t have to, Adric,” the other man says, smiling just a bit. “We have more than enough places to explore without new ones springing up all the time.”
“But I could do it. Look, I’ll show you. The TARDIS has a — a projector or something, doesn’t it? It must have. Let me give it a chance.” He’s stood up without even knowing it, and the TARDIS probably doesn’t even have a projector of any sort because why would it need one, but he wants very badly to prove what he said. He can calculate a world into existence and it won’t be a trap, it won’t fold in on itself, and it’ll have a proper history to it and a library with books on telebiogenesis and walls that wouldn’t crumble and no poison string of symbols for the Master to hide behind. And the Doctor could come back whenever he liked.
“You’re in no state to do any such thing.” The Doctor stands up, suddenly serious, and he really is smaller now; it’s not just the clothes making him look that way. “Stay here and rest. It’ll do you a world of good.”
“All right, all right, I don’t need the projector, then, just —” Just something, something to let Adric make sure this new Doctor’s as brilliant as ever he was. It won’t be the same, and there’ll still be no Romana, but it’ll be something. He’ll get used to the face and the voice, in time. He knows he will.
The new Doctor sighs, frowns a bit, and sits back down. “All right then, Adric,” he says, after a pause. “Show me. Go on, get a pen and paper. No! Wait. Don’t you move. I’ll get them.” He springs up — at least the sudden surge of energy when he has an idea remains the same.
He returns with another faint smile, supplies in hand. “Pens and paper; such a handy thing to have around. Never know where you’ll be when your next brilliant idea hits you.” He sets the papers in front of Adric. “Go on, then. Let me see it.”
So Adric writes, faster and faster, transcribes the formulae as fast as he can remember them as best in he can in the language that numbers afford him. It takes him maybe minutes to cover a single sheet of paper, and all the while the Doctor’s asking questions, making observations — spectacles balanced on his nose; he never used to wear spectacles.
After a while he runs out of paper, and the Doctor’s still looking over the second-to-last sheet so he doesn’t get him any more. So he gets up himself, without waiting. He can’t leave it incomplete because then he’ll forget it, or maybe remember it.
The Doctor keeps on trying to get his attention but he doesn’t stop until he’s finished. And then he looks up, and sees that the Doctor’s still reading. Upside down.
His brow furrows a bit as he comes to the last row, but after that he takes off his spectacles, smiles, and says “That’s brilliant, Adric. Not sure I would’ve thought of using a Varsaad proof for the relative coordinate stability.”
“Oh, I didn’t either, at first. But it just saved so much time, instead of working through it all the long way. Here, I tried it this way the first time…”
It saved time, he says like it was all about his own casual convenience. But he can think it was if he likes. And the Doctor’s looking over his calculations and correcting his transcriptional errors and he sounds almost like he did before if you don’t think about it too much.
And in spite of everything, Adric knows he'll get used to him.