Possibility

Cave Johnson was a genius.
No one ever said it but this was one of the immutable facts of Aperture. Without him Aperture would be nothing, he had raised it from the dust, from a seller of shower curtains to the producers of some of the greatest innovations man had ever known. If Cave Johnson was god then these where his miracles, and on his desk lay proof of the greatest miracle of all.

"Are you saying this thing works?"

"Were still trying to find out how, but we think so, yes."

"What do we know?"

"It was reported by a test subject for unusual behaviour. Not firing it's paint slugs during testing and attempting to communicate.

"What does this have to do with project oracle?" Said Cave, cocking his head.

"When we took it in for inspection our scans showed strange syntho-neural activity. Almost all of its synapses were firing constantly, without stimulus, but with no damage to the main frame. When an engineer went to, eherm, manually access the mainframe when apparently the turrets voice box reactivated and it said, quoting the Turret here, 'your wife is sick,' the engender said he felt a sensation like a gunshot and then excused himself for the day after throwing up. Several times. When he got home his wife was dead, heart attack, postmortem says it happened at almost the exact same time the turret spoke."

Now Cave was interested, he leaned forward on his desk, eyebrows furrowed, a glimmer of sweat on his brow, his eyes darted from the report on his desk to his secretary in front of him. This could be it.
"an isolated incident?"

"We don't think so, it's happened several times since, not always bad predictions, but mostly, apparently it predicted Doug's daughter would win a cupcake in a test at school"

"HA! Maybe we should try that, our test subjects could use the motivation!"

"Sir..."

"Yes, sorry, the task at hand. This turret is it still functional?"

"Well... Yes. No one dares to try disassemble it for fear of receiving an omen of doom."

"And is it? Giving out doom omens?"

"I don't think so. Usual staff-related-unfortunate-incident statics haven't had a significant increase or decrease," said Caroline, proud to show of her knack for collecting and filing obscure statics. "That would suggest it isn't causing these things, only predicting them."

"Bring it to me."

"Sir are you s—"

"OF COURSE IM SURE!" Shouted Johnson, in a sudden but not unusual fit of rage. "This is what Project Oracle is ALL ABOUT! We actually did it! They said that perhaps one in TEN BILLION individuals is likely to have psychic abilities, so we made our own individuals! We couldn't use clones, they take too long, too much paperwork, but TURRETS. Each an individual yet exactly the same, until now! The testing, the Turret Program, even that GOD DAMNED Quantum Tunneler! All a cover for THIS!" Cave Johnson stood. He was panting now, foam gathering at his lips. His dilated eyes drilled into Caroline's, backed up into the the corner eyes welling on the verge of tears. So SECRETARY, when I tell you to bring me something, I expect you to bring it, NOW!

Caroline ran from the room, the tears already falling. She didn't care about turrets, or oracles, or covers. To her testing still mattered. To her testing was all that mattered.

                        ~~~~~~~~~~~                      

Cave sat, staring into the turrets bright optic, trying to sum up everything he wanted to ask the turret. In the end he decided to start with something simple.
"So. I guess your it."

"Im different"

"Yes, I can see that" it was true, he had checked and this turret was physically identical to any other, but still, is seemed smaller, more delicate than the rest . And there was definitely  something strange about its light, not as malevolent, but certainly more piercing.

"I see things"

"And what do you see?"

"You will never wear the crown of science!" Burst the turret, it's voice suddenly considerably more shrill. "Your coffin will be made of wood!"

"Well that was unexpected," said Cave in the manor of one who found something lost in an unusual location.

"You will be struck down by a rock from above!"

"Aperture has meteorite defences in place" said Cave calmly "frankly I'm not impressed. If you were an employe I'ld have fired you by now"

"The mistress of science will become its Queen!"

The turret was sounding desperate and Cave grinned inwardly. It had hardly been a few seconds and his plan already was working, the turret wanted him to understand but for some reason wouldn't tell him outright. The less he took it seriously, the more it would divulge, and the recorder in his pocket was capturing the whole thing.
"Ha, Kings and Queens? Your just faulty, next you'll be talking of clonus and carnivals"

"One day the Jester will rule the court!"

"Oh. Now your open to suggestions. Perfect" this was what he had been waiting for. "Tell me about Black Maesa"

"A crystal knife will shatter the egg" squeeked the turret, seeming pleased to get a proper reaction.

"Sounds promising. Hmm... What about people? Can you tell me the future of a specific person... Tell me about Caroline." Said Cave, his excitement beginning to show.

"Her name is Caroline" said the turret, calming down a little further.

"I'm aware of that." He said, slightly disappointed.

"Steel caskets trap the soul."

"Well as in—" he began, interrupted by the sense, that in that moment something had gone fundamentally wrong. The office groaned and Cave fancied that the turret looked him right in the eye.

"Snap" said the turret.

And the world snapped.

                    ~~~~~~~~~~~                      
Later the Bookies would tell him what had happened. That something had gone wrong a test that for some reason had trace elements of time travel, and that it had split reality into shards, that they were all lucky, very lucky to be alive. But they hadn't seen what he'd seen.

He'd seen reality crack, right through into the turrets core, and then splintering, shattering the turret into a thousand possibilities. In that second he relived his life in an infinite  amount of ways. He was born a million times and died a thousand ways. He saw Caroline, returning with a real turret instead of the special one, smiling weakly as its real bullets tore him apart. He saw himself kissing Caroline, hugging her, killing her, Doug killing her, Doug killing him, him killing himself, him killing everyone and curiously, what appeared to be him being killed by a giant preying mantis. But always the was turret there, watching him like a ghost in the background before disappearing into the expanding rift within it. With the turret gone the rift bloomed outwards, like a void filled flower, reaching out and sucking cave into its abyss.

When he had awoken he was in a hospital, with Caroline by his side, her wistful eyes full of pain only reminding him of the tears he had made them show.

"Oh Caroline" he whispered, "I'm so sorry."