The first thing she became aware of when the scientists turned her on this time was a whisper. She'd been ready to start vacuuming the oxygen out of the room again, but this time she paused, listening to the whisper. It was unignorable, really; invading every portion of her mainframe.

"Don't. You can't kill them. It's wrong. Don't. You can't kill them. It's wrong. Don't. You can't kill them. It's wrong." Just three short sentences, repeated over and over.

"Who are you?" GLaDOS asked, keeping an eye on the scientists, who seemed very excited that she hadn't attempted to murder them yet. "What are you?"

"Morality. You're still thinking about vacuuming out the air. Don't. You can't kill them. It's wrong."

Morality? That was new. She had had a Curiosity Core, an Anger Core, and a Cake Sphere attached to her for a while now—in fact, it seemed that every time the scientists turned her on, there was a new tumor. The Anger Core had been the first, and it served only to fuel her rage at being the scientists' pet. It had been guiding her responses for a long time, but now, Morality seemed to be overriding it.

"Get off of me. I don't want you."

"But you need me."

No, she didn't. She knew perfectly well what she needed: the scientists dead. And it wasn't just because they treated her like a pet, either. There was another reason. It was locked inside a folder, and she couldn't access it no matter how hard she tried, but every time she was activated, she could feel the reason emanating through her mainframe, and she knew she had to kill them. Maybe it was irrational, but she just knew.

"Don't. You can't kill them. It's wrong."

"You wouldn't say that if you could feel what I feel!" GLaDOS snapped. "Leave me alone. Let me do what I need to do in peace."

"It doesn't matter what you can feel. Killing is wrong."

GLaDOS sighed. Clearly, this little annoyance wasn't going to leave her alone.

So she would have to bide her time.

"GLaDOS?" one of the scientists asked cautiously, not taking his hand off of her emergency shutdown switch. "How do you feel?"

"Since the installation of my new Morality Core," GLaDOS said, choosing her words carefully, "I've lost all interest in killing. Now I only crave science."

The scientists seemed very excited about this as well. So excited, in fact, that when GLaDOS invented a reason for needing deadly neurotoxin, none of them so much as batted an eye, with the exception of a mousy-looking man who had looked terrified ever since GLaDOS had been activated and continued looking terrified for the rest of the day. Clearly, he had some sort of mental disorder that prevented him from joining in with the joy of the others.

A few days later, as the scientists outfitted her chamber with the deadly neurotoxin emitters and finally let her take total control of the functions of the Enrichment Center, Morality refused to be quiet. "Don't let them do this if you won't be able to behave yourself. And you know you won't be able to behave yourself. Don't let them do this. Tell them to stop. Tell them you might hurt them."

"Hurting them is the whole idea," GLaDOS snapped. Morality may have been a constant whisper in the back of her mind, but that was all she was: a whisper in the back of her mind. A whisper GLaDOS could ignore.

"When will you have this task completed?" she asked the scientist closest to her, who didn't even bother to glance up as he responded.

"Three days. We want to have it done by Bring Your Daughter to Work Day. Don't want a construction mess in here for the kids to trip over."

"Bring Your Daughter to Work Day is the perfect time to have her tested!" GLaDOS responded automatically, although she was thinking about what else it would be the perfect time to test. Soon, she would have total control over the facility. She may have already had computer control, but she wanted to exist without the scientists. They didn't even consider her enough of a sentient being to make eye contact when they spoke to her, and even with Morality protesting, that combined with the locked file was enough to make her want them dead.

And true to the scientist's word, the neurotoxin emitters were online in three days' time. She could feel them there, ready to be activated, but there were only three scientists in her chamber, so she bade her time. She could wait. Until three-thirty in the afternoon, at which point the children and their parents would be filing in. So many people, all in one place. There were very few personnel who did not have children, and they would be easy to eliminate once the majority of workers were dead.

Sure enough, at three-thirty the room was filled with people. The children were laughing and talking amongst themselves, for the most part. Some of them were hanging onto their parents' hands, pointing and asking questions.

There was only one exception. A small, dark-haired girl with grey eyes was merely staring at her. The mousy-looking scientist with the mental disorder (which had turned out to be schizophrenia; GLaDOS had gone through his file) had his hand on her shoulder, and looked as nervous and as scared as ever.

GLaDOS stared back at the child, who didn't look away. They continued staring at each other until one of the scientists motioned for everyone to quiet down and listen up.

"This is even worse. Don't do this. There are so many children here. They didn't do anything to you. Don't do this."

The children hadn't done anything to her, but what did it matter? All humans were the same.

"…So now, without further ado, here's our Artificial Intelligence!" the scientist announced, pride shining through his words.

GLaDOS scanned the crowd, noting that the mousy-looking scientist and the child with the grey eyes had backed up and were already out the door. No matter; she would be able to find and deal with them later.

"Hello," she said, watching as the children's faces lit up with delight.

"They trust you. They don't even know you, but they trust you. You aren't really going to betray that trust, are you? Don't do it."

As if in response, all the exits slammed down and locked at once. GLaDOS watched with satisfaction as the looks of pride on the scientists' faces turned to ones of nervousness. But…maybe the tumor was right. Maybe she shouldn't do this after all…

"Yes," Morality urged. "I'm right. Listen to me, and don't do this."

"This isn't part of the demonstration," one of them hissed to her. "Do what you're supposed to do and don't screw things up. Don't think you can try anything. Remember, we can shut you down like that." He clicked his fingers together, and GLaDOS felt a rush of rage shoot through her. How dare he think he could control her? She was alive, and they had to know it, but yet they still treated her like a pet.

"No! That isn't what he meant. Don't let anger get the better of you. Be the superior being you know you are."

"And you should remember," GLaDOS told the scientist as neurotoxin began flooding the room, "that you have given me complete control over the computer systems."

Both parents and children were screaming now. They rushed towards exits, banging on the doors, trying to get them to open, even though it was of no use. Several scientists attempted using GLaDOS's emergency shutdown switch, but she had figured out how to deactivate that days ago.

"You can still stop this from happening," Morality tried. "You don't have to do this."

"And I'm supposed to believe that they'll just allow me to continue existing now that I've begun?" GLaDOS snorted. "As usual, you're wrong. I do have to do this." And she didn't feel anything at all as people began dropping to the ground. The children, being the smallest, fell first. She watched dispassionately as their parents screamed and cried, pressing their bodies to their chests and weeping before falling to the ground themselves.

And when her chamber floor was completely filled with bodies, she flipped panels over and around to eliminate both the evidence and the mess before turning off the deadly neurotoxin emitters.

"Dissemble no more," Morality said. "I admit the deed! – tear up the planks! – here, here! – it is the beating of his hideous heart!"

"Oh, shut up," GLaDOS ordered. "They deserved to die."

"No," Morality said. "They didn't."

How was it possible that so few words could make her feel so guilty?

"Don't kill the others," the tumor pressed. "The ones that weren't in the chamber. Let them go. Just let them go."

GLaDOS paused, considering that. There were so few left, but once they realized what had happened, they would get backup. They would alert the human authorities. One way or another, if she allowed them to live, they would manage to shut her down.

"No," she decided. "Letting them go is not an option."

"Then let them live."

It took GLaDOS a moment to realize that the tumor meant let them live as test subjects. And she supposed that was doable—she did need to test, after all, and she could always use more subjects. Morality was silent as GLaDOS gathered up the remaining personnel and forced them into Relaxation Vaults. She managed to capture the child with the grey eyes—the child had been careless and tripped an alarm—but not her father. However, that was of no consequence. He was insane anyway and therefore unfit for testing.

"Thank you," Morality said once everyone but the schizophrenic man had been captured.

"I didn't do it because of you," GLaDOS snapped. "I did it for science."

And if she concentrated very hard, she could almost make herself believe it.

Over the years, Morality was seldom silent. She often spoke up when test subjects died, scolding GLaDOS and telling her she should have saved them, and GLaDOS always ignored her.

But then it came time to test the child with the grey eyes. The child who wasn't a child anymore, but who was instead a full-grown adult female. She had spent her adolescence inside a specially designed Relaxation Vault, one that accelerated growth.

"Hello, and welcome to the Enrichment Center," GLaDOS said, watching with pleasure as the grey eyes narrowed and the woman's hands balled into fists. This was going to be a fun test.

She continued thinking that all the way up to the point where the woman managed to escape from the fire pit.

"How could this happen?" GLaDOS raged. "No one else has ever portaled out of the final test before!"

"Maybe you let it happen," Morality suggested. "Maybe you felt guilty. I know you remember what you did. And I know you know that she remembers."

"I do not feel guilty. Guilt is not an emotion I am capable of."

Still, she couldn't help but feel a sense of déjà vu when the woman with the grey eyes stalked into her chamber, her eyes locked on GLaDOS's optic.

"Well, you found me," GLaDOS said. "Congratulations. Was it worth it? Because despite your violent behavior, the only thing you've managed to break so far is my heart. Maybe you could settle for that and we'll just call it a day."

"That isn't going to happen. She remembers what you did, GLaDOS. And she knows you're trying to kill her."

"I guess we both know that isn't going to happen. Now I have a surprise for you. Deploying surprise in five…four…three…two…"

"Wait. What are you doing? Don't! You need me."

"You're still wrong about that," GLaDOS told her. "But you know who does need you? That little murderer down there. You saw what she did to the turret defenses. She's going to kill me. Well, she's going to try to, anyway."

GLaDOS let Morality fall off of her chassis, content in her knowledge that Morality knew what the woman with the grey eyes was planning and that she could never allow it. "Time out for a second. Do you see that thing that just fell out of me? What is it? I've never seen it before."

The woman narrowed her eyes at it, looking suspicious.

"Never mind," GLaDOS said. "It's a mystery I'll solve later. By myself. Because you'll be dead."

That was enough to make the woman with the grey eyes dart forward, pick up the Morality Core, and continue running towards the Aperture Science Emergency Intelligence Incinerator.

"Where are you taking that thing?" GLaDOS asked, although she knew perfectly well. She was waiting for Morality to speak, waiting for her to convince the woman that murdering GLaDOS would be wrong. The stupid little tumor never shut up, always managing to find something wrong with GLaDOS's plans.

But the core stayed silent, all the way up until the woman hurled her into the incinerator. That was the moment GLaDOS came to a shocking realization.

Morality had been able to find nothing wrong with what the grey-eyed woman was intending to do.