The Doctor craned his neck to get a better look at the thing embedded behind the panel in the wall.
"This is quite impressive," he commented. All Donna could see was a sleek metal dome and a few flashing lights. "And you have these all over the station?" He asked, sounding incredulous.
"Yes," Joanna replied, obviously pleased with herself. "We'll get data from every inch of the place."
"Yes, but what are you going to do with it all?" The Doctor asked. "You're talking about a truly massive set of data. The processing power you'd need to make sense of it all… this supercomputer of yours has to be quite something. I'm not sure… oh." His tone changed, suddenly flat. "Oh, I see now." He leaned back out from behind the panel and smiled up at Joanna. "This is a trap, isn't it?"
Donna blinked. What?
Joanna stiffened slightly, and she saw the two men with her reaching towards their sidearms.
"It doesn't have to be," Joanna said carefully. "You could volunteer."
"Volunteer?" The Doctor repeated incredulously.
"What are the two of you going on about?" Donna demanded, irritated. They both looked at her, Joanna seeming surprised that she was still standing there, the Doctor looking deadly serious.
"They need a super computer so powerful that there's no artificial processor made that could possibly run fast enough for it. They need the kind of complexity that you only find in the brain of a sentient being. And unless I miss my guess, a rather cognitively advanced being, at that. Such as, for instance, a Time Lord."
Donna blinked, looking from the Doctor to Joanna. The other woman made no protest or denial.
"You… you want his brain?" Donna said, horrified.
"No need to be so dramatic about it," Joanna chided. "It's not as if we're going to open up his skull and take it. The system is designed to run with a living person as the processor and maintain all of their vital functions while they're plugged in. It's quite safe. I've tried it myself."
Donna's jaw opened and closed a few times. There didn't seem to be anything to be said in reply to such a statement.
"You won't feel a thing," Joanna continued, addressing the Doctor. "It's like being asleep. You'll be in and out before you know it. Just let us borrow you for long enough to cure this plague, and you're free to go your way."
"Even with all the data you get from this station, that will probably take years," the Doctor pointed out.
Joanna shrugged. "What's a few years to you? In the lifespan of a Time Lord, that's a drop in the bucket."
"And Donna?" the Doctor pressed. "Are you going to let me take her home, first, or is she just going to be waiting around until you're through with me? A few years aren't just a drop in the bucket to her."
Joanna sighed. "I'd like to say yes, but I have no illusions that if I let you go now you'll ever come back. You have a bit of a reputation, you know."
The Doctor nodded. "Just one more question. These 'immunes' you think you've located. Are you giving them the option to 'volunteer'?"
Joanna said nothing. But she didn't need to. The answer was written all over her face. The Doctor's hand made a sudden, quick movement behind the panel, and Donna was blinded by a flash of brilliant white light. Joanna and her men cried out in surprise. Donna felt a hand close around hers and pull her into a run.
"Come on!" the Doctor's voice said urgently in her ear.
Donna blinked away the rush of memory.
I remember, she typed slowly.
She looked back at the Doctor on the table behind her, muttering and insensate. There were wires coming out of the bottom of the table at points all along his spine. There was another big bundle of wires near the back of his neck, right at the base of his skull.
Does it hurt? She finally typed.
No, not at all, the Doctor replied at once. I think most of my nociceptive neurons are actually completely shut down at the moment.
Donna nodded dumbly, still trying to wrap her mind around it.
Really, the Doctor continued, it's been kind of fun since I got the hang of it. But I am more than ready to come out now.
Right, Donna typed, her thoughts beginning to approach their normal speed. There was still work to do and not a lot of time to do it. How do I get you out?
I'm bringing up the protocol for extracting me now.
The screen on an adjacent monitor suddenly changed. A file appeared with a diagram of what looked like the bed the Doctor was lying on. The outline of a person was sketched on top of it, and the diagram was numbered at various points. Next to the diagram was a large block of text divided into numbered steps. The floor bucked a bit and Donna felt a small explosion reverberating through the floor and into her chest.
Read this over carefully. Take your time, and let me know if there's anything you don't understand. Once you get past about step seven I'm not going to be able to respond anymore, so you need to be sure you know what you're doing before that.
Donna bit her lip, looking at the long lines of technical instructions.
Remember the mind wiper, Donna, the Doctor said. You handled that, you can handle this. I have faith in you.
Donna set her jaw and set to work. Step by step, she told herself, and set to reading. Step 1. She put a finger on the screen and ran it along under the words as she read them, trying to focus and untangle the dense descriptions.
"Primary neural interface adaptor," Donna read. "What's that?"
That'd be the big plug in the back of my head.
"And these 'secondary cortical extensions' I need to retract?"
Ah, you can't actually see those, they're internal. That'll just be something you have to click in the neural interface submenu. Ooo, hold on I've got an idea.
The extraction protocol disappeared for a moment and a different window opened. Frenzied lines of code appeared on the screen, some incomprehensible program writing itself into existence. The protocol appeared again and a few parts of the diagram flashed red in turn. An error window appeared. The code came back, adjusted itself, then disappeared again. The protocol reappeared.
Alright, any term you don't understand, just mouse over it, the Doctor instructed.
Obediently, Donna swung the cursor over to where she had read primary neural interface adaptor. The words lit up red, as did the part of the diagram showing the big plug. Donna smiled.
"This'll help."
She moused over secondary cortical extensions. On the diagram, a network of red lines lit up inside the person's head, connecting back to the end of the big plug. Donna shuddered. With the Doctor's new program running she soon felt she had a reasonable grasp on what all the different parts of the machine she was required to manipulate were. It would still be some time yet before she understood what she was supposed to do with them all.
"So when it says disconnect the primary adaptor I just pull it out?"
No, no, no, no! 'Disconnect' means tell the computer to stop communicating with it. If you just pull it out while I'm still connected you're going to give me some kind of horrible mental whiplash.
"Right, right sorry… so that's one of the things in this menu over here?"
Right. Up until step nineteen you're just working on the computer, shutting down all the links between me and the machine. Then you can start removing the hardware.
"Ok."
Donna went over the protocol a few more times, muttering to herself and tapping the screen.
"That'll be an option over here, check this box, this box, and that one… close all biomonitoring programs… remove temporal and maxillary leads…"
The floor of the station shook again, and this time the lights flickered. The tremors had been getting more and more insistent while Donna had been working, and it seemed as if the temperature in the room had risen a few degrees, although she might have been imagining it.
"How much time do we have left?" Donna asked.
Fifty eight minutes, fifty two seconds, the Doctor reported. A screen on the other side of him had switched to displaying a diagram of the station's orbit around the planet and a long list of figures describing their situation as the Doctor spoke. Donna shook her head. No wonder his time estimates had always been so precise.
"Alright, I'm going to get started."
You're sure you're ready? You still have plenty of time, Donna, there's no need to rush.
Donna shook her head.
"I'm as ready as I'll ever be. I'm getting you out of there, Doctor."
Be careful, he said. And thank you.
Donna exhaled deeply, and set to work as the floor below her shook and creaked ominously. Carefully, deliberately, she opened each menu in turn, checking and double checking her instructions. Click here, then here, then there. Close. Next menu. Before long she had reached step seven. She paused, mouse hovering over the last button.
"What about Joanna's people? Will they be able to get in here once I disconnect you?"
A lot of them have already been pulled away to help with the evacuation. I'll lock down everything I can before you pull me out. It won't be as effective without me controlling it, but it should still buy us enough time.
"Alright," Donna took another deep breath. No more life lines after this. "Talk to you soon."
She clicked the button. Nothing really seemed to change, but somehow the room still felt emptier.
"Sixteen, forty-two, forty-two, zero, nine, one, twenty…"
Donna was lost in a maze of menus and submenus. All the names were beginning to look alike. Was trigeminal impulse routing the menu she was looking for or was there actually another menu called trigeminal impulse route somewhere that she had overlooked? Most times the answer became obvious with a few minutes of searching, but once or twice Donna was forced to simply guess, feeling extremely nervous as she did so.
Finally, all that remained was to disentangle the Doctor from the mess of wiring that surrounded him. Carefully, she lifted the wiring away from his face and let it drop to the bed on either side of his head.
"Four, eighty-seven, ninety-one, fifty-two, seventy, seventy, forty-four, four…"
The Doctor's strange litany had never slowed. Donna crawled underneath the table and began pulling out the spinal leads, one by one, working her way up the Doctor's back to his neck. Finally, only the great plug at the very base of his skull remained. Gently, Donna took hold and pulled the thing out.
"Sixty-three – "
Silence. The Doctor stopped speaking, and the sudden absence of the numbers was so stark Donna almost felt dizzy. Coming out from beneath the table she stood and regarded the Doctor anxiously. He'd closed his mouth. His eyes were still flickering back and forth, like before, like he was looking for something. But a slight frown line had appeared between his brows. He blinked, and then his eyes flicked to her face. For the first time they stopped. Then they focused.
"Donna!" The Doctor cried, breaking into a grin. "You did it!"
He threw himself up and made it half way to a sitting position before he suddenly cried out and collapsed back to the bed, groaning and throwing his arm over his eyes.
"Oh…" he moaned. "Oh, now it hurts."
"Are you ok?" Donna asked, alarmed.
"No!" the Doctor snapped. "I have got a headache like you would not believe!" He shifted his arm to uncover one eye and regarded her seriously, shaking an admonishing finger at her. "Never use your brain to run a supercomputer, Donna," he said. "It's very uncomfortable."
A horrific grinding noise filtered up through the floor and the room bucked.
"Alright, help me up," the Doctor said, holding an arm out to Donna. "I haven't moved very much in a while, so I don't know how well this is going to go."
Donna helped pull the Doctor up into a sitting position, putting his arm over her shoulders and lifting him up with her arm behind his back. He swung his legs over the edge of the bed, preparing to stand.
"It was you," said a voice in the doorway, sounding shocked, betrayed. Both their heads spun toward the door. Nancy was standing there, holding a brown leather bag, staring at them with wide eyes. At first Donna thought the young woman was talking to her, but she realized it was the Doctor who held her gaze. "They told me it was you, but I never thought… it shouldn't have been possible, and besides… why? We did our part."
"Because this isn't right, Nancy," the Doctor replied, through gritted teeth. "I know you know that."
"We aren't hurting anyone," she whispered plaintively.
"This is what you meant, isn't it?" Donna said sharply, the pieces slowly coming together in her head. "This is what you meant when you said you 'took care' of the central computer. You knew!"
The room shook again and the lights went out for a few seconds.
"Look," the Doctor told Nancy, who still stood, stunned, in the doorway. "It's done now. You can either help us or get yourself to an escape pod, but I'm not going back in there." He nodded toward the head of the bed behind him. Then he nodded to Donna and slid off the bed and onto his feet.
With Donna supporting him his legs managed to hold him for about half a second before his knees buckled. The Doctor grunted in surprise and his weight bore them both to the ground. Donna managed to bring him to rest in a sitting position at the base of the bed. He leaned back against it and groaned in frustration.
"Oh," Nancy sighed in resignation. She hurried across the room toward them, pulling her bag open in front of her. "Here, let me."
She dropped down on the other side of the Doctor from Donna, pulling some sort of metal cylinder out of the bag.
"What's that?" Donna demanded suspiciously.
"It's alright, Donna," the Doctor said, allowing Nancy to tilt his head slightly to the side and press the metal cylinder up against his neck. "We can trust her."
There was a quiet hiss and through a window in the side of the tube Donna could see a cloudy liquid vanish. Nancy pulled the empty cylinder away and tucked it back into her bag, rubbing her thumb twice across the injection site.
"Trust her? She's the one who plugged you into that thing!" Donna protested.
"And kept me safe while I was in there," the Doctor replied. "Not to mention looking after you at my request. Trust me, Donna. If it weren't for Nancy, I would be a lot worse off than I am right now."
Donna turned a measuring gaze on Nancy, who turned her eyes downward, her posture stiff as she rooted through her bag.
"That was a nanomusculoskeletal reinforcement," she explained. "The system was designed to limit musculoskeletal degeneration during prolonged recumbency, but some amount of atrophy is unavoidable. The nanobots will integrate with your remaining musculature and strengthen it until you've had a chance to recover." Her hand came back out of the bag holding a penlight. The room shook around them. "We'll need to give that another minute to start working."
"You came prepared," the Doctor noted.
"I was coming to get you out of here," Nancy replied sharply. She tapped the Doctor on the back of the head until he leaned forward enough for her to inspect the site where the plug had been. "Joanna still thinks she can save the place somehow if she gets to you, but we're not repairing blown orbital thrusters with a supercomputer. This station is going down, and I didn't think anyone else was worrying about getting you off it. I didn't realize I was dealing with an escape attempt in progress."
"How did you get in, anyway?" the Doctor asked.
Nancy shrugged and allowed the Doctor to lean back again, evidently satisfied with the state of his neck. She shined the penlight into his eyes, examining first one, then the other.
"I bypassed the lock on one of the doors. Everyone else has given up trying that, but I thought maybe I could manage it. Look here," she commanded, holding up a finger. She slowly moved the finger up, then down, watching the Doctor's eyes while they followed it.
"You must have tried it after Donna disconnected me from the infrastructure. It would work for anyone now that I'm not there to oppose it."
Nancy brought her finger level with the Doctor's eyes again and moved it left to right to left a few times, frowning at what she saw.
"Well, it looks like she didn't get you quite cut off from the data stream before she unplugged you," Nancy said, shooting a look at Donna that was so quick Donna almost missed the hint of disapproval in her eyes. "I don't envy the headache you must have, but there's nothing I can do about that now. You'll just have to wait until it passes." She did not sound terribly sorry about this as she clicked the penlight off and returned it to her bag. "Otherwise you look fine. Side effects should be mild, but you can probably expect some lack of coordination while your nervous system re-adapts to its original function."
"Brilliant," the Doctor said. "Thanks for that."
"Thanks for dooming my planet," Nancy responded, zipping her bag shut. "Now see if you can stand."