Chell first knew something was wrong when she stepped off the elevator and GLaDOS greeted her without insults. "Hello, Chell!" And it wasn't just without insults. The AI sounded perky and cheerful in a way Chell had never heard her sound before, and it set the human on edge.

"Hi," she replied carefully, inching her way out of the elevator and towards GLaDOS. "Are you all right?"

"Of course I'm all right," the AI replied. Under normal circumstances, it would have been a sarcastic reply, but she maintained the cheerfulness and even sounded a bit worried. "Why? Do I not sound all right?"

Chell shook her head, keeping her eyes locked on her friend. "Really? Your self-diagnostics don't turn up anything…funny?"

"Can you just tell me what you think is wrong?" GLaDOS asked, then as an afterthought, added, "Please?"

Now Chell was really worried. She shook her head, taking a step back. "I…look, can I just…I don't know, would you let me in your control room so I can take a look around?"

It wasn't like she was actually expecting the AI to let her in. Even though Chell had majored in programming at a nearby university, GLaDOS had told her countless times that she would never be allowed to interfere with any of the crucial functions of Aperture. It wasn't like Chell had ever even asked about it before. GLaDOS just wanted to make certain that the human knew where she stood.

So when two panels in the wall of the AI's chamber slid aside to reveal a small room filled with switches and buttons, Chell was shocked, to say the least. She looked up at GLaDOS with a frown. "Are you sure?"

"Of course I'm sure," the AI replied, as cheerful as ever. Chell had to wonder what had happened since she'd last visited three days ago. "Why wouldn't I let you in? I trust you."

"You do?" Chell asked, staring. Her friend just nodded in response, and Chell's worry levels went so far off the charts that she raced into the control room at top speed. Once she was inside, though, she couldn't help pausing for a moment to look around. It was not what she'd expected.

Instead of being sleek and white like the rest of the Enrichment Center, the control room's walls were covered in peeling paint. It was almost what could be called ratty. It was like a piece of old Aperture had been cut out and inserted into the newer portion. The human turned to face GLaDOS, a question on her lips. But before she could ask it, the AI interjected cheerfully, "The control room is the only portion of Aperture I am unable to access. But I don't need to. It is obsolete. I have complete control over myself and the entire Enrichment Center."

Chell snorted, not bothering to respond. If that were true, what had GLaDOS done to herself?

The human walked in a circle around the control room, looking for something out of the ordinary. Unfortunately, though, she wasn't sure what she was looking for. She had no experience with technology as outdated as this.

But then she saw it. It was a chance sighting, brought forth only by her examining the buttons and switches for what had to have been at least half an hour. GLaDOS had been chattering cheerfully on for the entire time, and Chell had been trying to tune her out. Hearing about how happy the AI was just made her even more jittery.

She ran rather than walked over to the button. It was small, and half-covered by dust, but she could still read the lettering. It read "GLADOS EMERGENCY REBOOT," and she frowned as she stared at it. A reboot might fix whatever was wrong with GLaDOS, but what if the facility exploded without her controlling it? After all, Chell had no idea how long a reboot might take…

…And besides, this new version of GLaDOS was creepy, but a hell of a lot nicer than the old one. Wouldn't Chell rather just keep her this way? Maybe the AI had even done this to herself on purpose for some reason.

Chell didn't really believe that, but still, the thought was tempting. She took a step back from the button and looked through the opening at the chamber. From there, she could hear GLaDOS humming to herself.

That in itself was enough to make the human lean forward and jam her finger onto the button.

There was a loud noise, and then all the lights flickered off for a brief moment before coming back on. All the monitors in the control room now displayed a loading screen that read "GLADOS REBOOT AT 29%," and Chell turned her attention to the chassis that was now dangling limply in the middle of the chamber. She crossed her fingers.

It didn't take too long for the monitors to read "GLADOS REBOOT AT 100%" and for the aforementioned AI's chassis to swing to life. Chell stared at her from inside the control room, watching with bated breath.

"Whaaaaaat—how long was I out?" GLaDOS asked, sounding a lot like she had when she was in the potato battery. Her chassis swiveled around, looking for some sort of response, then locked on Chell and narrowed. "What are you doing in there? Get out. Now."

Chell exhaled in relief, then rolled her eyes. "You call that a thank you?"

"Thank you for what?" the AI asked. "I know you think you've helped me in some fashion, but you haven't. Really, what you walked in on was just a simple glitch caused by the lightning storm two nights ago. Sooner or later it would have straightened itself out, with or without your assistance. So get out."

The human's eyes narrowed. "Yeah, and exactly how late is 'later'? I think I just saved you a hell of a lot of embarrassment."

"How so?" the AI asked, still sounding more irritated than curious. "And get out of there. Right. Now. There is sensitive equipment in there. The last thing I need is for you to break something."

"Because it—" Chell's eyes narrowed even more. "You know what? I don't think I will."

"I'm warning you," GLaDOS began, her voice dangerously low, but the human ignored her. She made her way over to an interesting set of buttons she'd noticed during one of her earlier circles. One pointed up, and the other pointed down. The buttons were right in front of a monitor that had a sticker reading simply "GLADOS CNTRL" on the top of it. The monitor itself displayed a status bar that rested in the middle of the screen, unmoving.

"Like that," the AI said. She was craning her chassis to see as far into the control room as possible. "That is one of the things that you could break. So get away from it. Now."

"You're so unappreciative," Chell said, hovering her hand over the down button. "I was worried about you. I didn't know it was just a glitch, if that's really all it was. I thought something might be really wrong."

"Then that was your mistake," GLaDOS snapped. "This is your last chance to get out of there before I rescind your welcome."

Chell slammed her hand down on the button. The status bar dropped, and the AI let out a scream of pain. As soon as the human removed her hand, the bar returned to its original location, but GLaDOS was silent with the exception of some gasps that were tinged with simulated pain.

"It's real to them," Chell remembered Wheatley saying about the turrets in the incinerator room back when they were working together, and instantly felt guilty.

"GLaDOS?" she asked, staring into the chamber. The computer's chassis hung limp, but after a moment it moved, and GLaDOS raised her head just enough to glare at the human.

"If you ever do that again—"

Chell's anger flared, and she slammed her hand down on the button again. "Stop threatening me! Every time I'm here, that's all you do! Even after I saved your stupid ungrateful life the first time, that was all you did. Stop it!"

GLaDOS let out another scream of pain, but this time Chell didn't let up. The status bar dropped almost to the bottom of the screen, and it wasn't until lights began to flicker that the human released the button.

But unlike before, the status bar didn't rise back to its original position, and the AI's screams only slightly lessened.

"GLaDOS?" Chell asked, beginning to feel panicked as the screams continued. "GLaDOS!" There was no response or even a sign that her friend—well, she didn't think GLaDOS was going to continue to consider her a friend after this, but still—could even hear her. Was this how the scientists had controlled her?

After a few initial seconds of panic, Chell slammed her hand onto the up button, holding it down, and the status bar shot up. GLaDOS's scream seemed to catch in the throat she didn't have, turning into a gasp. The human removed her hand from the button, watching the computer with curiosity.

"What—what are you doing?" GLaDOS's voice was barely audible. "I—thought I told you to—get out of there—"

"I'm sorry," Chell told her, and she meant it. "I know. I'll get out now."

"No!"

Caught by surprise with the forcefulness in GLaDOS's voice, Chell stopped. "No?"

"No," GLaDOS repeated. "I mean—if you leave that room, I will release a deadly neurotoxin. And then you will die."

Chell's eyes narrowed. She crossed her arms and sat down on the ground. "I said not to threaten me." And for a moment, the two just glared at each other, but then GLaDOS sighed.

"Fine. I will not release a deadly neurotoxin."

"No?" Chell asked, her eyebrows raising. She'd never known the AI to back down so quickly before.

"Just…push that button again."

"That button hurt you," Chell protested, standing up. "I'm not pushing it again."

"Not that button," the computer sighed. It was clear that she was trying to sound exasperated, but there was a note of desperation in her voice that hadn't been there before. "The other one."

Keeping her eyebrows lifted and her eyes locked on GLaDOS, Chell walked back over to the buttons. She stared at the supercomputer for a moment, who seemed to be tensing up, then slammed her hand down on the up button.

The AI's chassis tensed even more, and instead of a gasp this time, she let out a loud, shuddering moan. Upon hearing that, Chell yanked her hand away from the button, disgusted. "What the hell? Is—wait. Is this your testing euphoria control?"

"Ye-es," GLaDOS gasped as the status bar dropped, stopping just a bit above the center. "I never—don't stop—"

"You can't be serious," Chell protested. "I thought you were in this for the science."

"I am in this for the science," the AI argued, her words becoming easier to get out. "But you don't have any idea what it's like, to have this itch all the time and never be able to fully scratch it because the idiots who created you have it set so that—hnngh—"

Chell wasn't sure what made her slam her hand down again, but she was pretty sure it had something to do with wanting GLaDOS to just shut up for once in her life. Unfortunately, that wasn't working. The computer was quite vocal even now. Chell waited a moment before releasing the button again.

"What—" the AI managed to choke out before Chell slammed her hand down again. She didn't hold it down for very long at all this time, instead releasing and holding it down in brief intervals, GLaDOS moaning with pleasure all the while. Chell had needed some way to get what she wanted out of the computer, and she wasn't willing to hurt her for long, but this?

This she was willing to do.

At last, when she let the button go at the end of one of her hold-release cycles, the status bar was nearing the top. She knew the supercomputer was expecting her to slam her hand down and finish the job, but that wasn't going to happen. Not just yet.

"What—what are you doing?" the AI gasped at the hesitation. "You're—you're not done yet—"

"I thought you were rescinding my welcome," Chell said, the ghost of a smirk playing around the corners of her mouth. While it had been fascinating to watch the giant computer writhe helplessly in simulated pleasure that was only real to her, this had been what she was after in the beginning and this was what she intended to get.

"You can—have it back," GLaDOS managed. "Now—finish—please."

"No," the human said, calmly stepping away from the buttons and folding her arms. The AI stared at her, desperation evident in her gaze as the status bar took a slight drop. "You still haven't said thank you."

"Fine," GLaDOS spat out without hesitation. "Thank you."

"For?" Chell prompted.

There was no answer as the status bar dropped a bit more, and the human tapped the button down for just a brief second, extracting nothing more than a sharp inhale from the AI as the status bar rose back up. "For?" she prompted again.

"For helping me," GLaDOS gasped. "It—would have taken—a while to diagnose and—fix—so—thank you—"

That was all Chell needed to hear. She slammed her hand down on the button for the final time, holding it down as a scream erupted from the giant chassis, causing the lights to flicker like they had earlier. But this time, GLaDOS wasn't in pain, and as Chell gently released the button, the status bar dropped down to a bit below the center. The chassis had been seized up against the ceiling, and as Chell's grip on the button relaxed, so did it, sagging until it almost touched the ground. There was no sound save for the ragged "breathing" that was apparently part of GLaDOS's sound files, but still the human didn't leave the control room. She wasn't sure how GLaDOS was going to feel about all this now that it was over, and if she needed to run, she was going to make damn sure she got a good fighting chance.

After a moment, the AI raised her head and stared at Chell, who stared back, her heart thudding and her hand cupped over the down button just in case.

"…thank you."