Jack knew Carter wouldn't be happy about the summons to the conference room – and probably even less happy about its cause. He met her at the top of the spiral staircase, knowing well the off-kilter route she always took from her lab through the Control Room "just to check on things," with a cup of fresh coffee.
"Thank you, sir." Eager hands wrapped around the mug, and she was halfway through her first sip when she saw the man sitting on the other end of the conference table.
To her credit, there was no spit-take. She didn't even choke. She just tipped the cup down a tiny bit, swallowed her coffee, and said into the mug, "This is a waste of my time."
The hard ceramic reflected and twisted her words, and Jack was pretty sure the other man didn't catch them. Jacob, however, did. "Sammie, if he can help...."
"He can't. And we're wasting time." Mug hit table with a slosh as the newcomer's eyes ever so slowly swept up her uniform, taking in every curve. He was really pushing it, Jack thought, and ordinarily he might have stepped in. His second, however, was well armed in dealing with this particular problem from this particular man. "But don't let him leave without lunch," Carter added. "I hear it's lemon chicken day."
It wasn't, and Jacob's mouth opened to correct her, but Rodney McKay pushed to his feet first, looking more than a little shocked. "I take it we've met," he said slowly.
"In two too many timelines," she retorted. "I'm going back to my lab."
"You might like me once you get to know me!" he called, and she whirled to face him.
"You're forgetting – I do know you. So that's not helping your case."
"Nonetheless, he's going with you." When Carter gave her father a stare like he might as well have just hopped on the massive table and done a jig, he shrugged. "You always told Mark when you helped him with his Calculus that two heads were better than one."
The stare slowly morphed into a look of complete disbelief. "Mark failed Calculus," she growled. "And you grounded him for a month and he moved out the next day. So I never said that. And even if I had, it would have only been to make him feel better. It was a lie."
~/~
Rodney McKay went largely ignored – completely ignored by Carter – as he stared at the five whiteboards bleeding equations. The major, as Jack had figured, went straight back to the sixth and relatively unscarred board, working on yet another series of calculations that didn't seem to contain a single real number. Letters and exponents reigned supreme.
Twenty minutes later, when McKay finally spoke up, Jack thought him fairly fortunate to still be alive in their former reality, much less still working for the Air Force. He wondered idly if Carter had perhaps privately castrated the man and McKay had been to embarrassed to admit it.
"This is wrong," he said.
She turned to him like a tiger that had just located its latest prey – slowly, dangerously – and Jack seriously considered leaving just so that there would be no witnesses to what might happen next. "Excuse me?"
"This is wrong."
The red marker hit the floor with a subtle click as her hands spasmed and flexed in supreme irritation. "Can you be more specific?"
"This." He waved his hand under a line on the second board. "You've introduced a variable that doesn't, shouldn't, and won't exist. And if everything past that is based on this, you might as well erase all these boards right now."
Suddenly, Jack was glad she'd dropped the marker – it likely would have found its way into the egotistical man's eye or some place equally vulnerable. And that thought made him shift in his chair. "Carter," he soothed softly.
"That variable," she pressed, "stands for the amount of additional entropic force generated by the presence of duplicate people in one reality. And it's not wrong."
"You can't know that," he argued.
"I can't...." Swooping down to snatch the pen from the floor, she crossed the room to the second board. "I can know that. Everything from here -" she drew an angry vertical line near the start of the second board, "to here -" and another strong line appeared down the middle of the fourth board, "is fact. I've lived it. So don't tell me my math is wrong."
"You make it a habit to travel to other realities?" he snapped, obviously not happy at being pulled up quite so short.
Jack resettled against the far wall. "Actually, another Carter came to ours."
He turned back to the woman with a snort. "Another you?"
"Yes, another me," she shot back.
"And she suffered this... this...."
"Entropic cascade failure."
"How long did it take to set in?"
Jack was really hoping Carter would remember that one and not glance his way, thus making him admit that he remembered pretty much every minute of that very strange visit. But luck had never really gone his way, and she shrugged at him. "Three days," he supplied. "Well, two and a half, I guess."
The shorter man chewed on that for a moment, irritation replaced by puzzlement. "But that Major Carter was military, too."
He shook his head. "No."
"Well... but... then how did she end up in an alternate reality?"
"She was a civilian contractor," Carter supplied. "Like you. Stationed at the SGC."
"So.... Still, that reality was much closer to yours than this one."
"Hell, yes!" Jack answered emphatically. Except for the facility itself, which had existed far before the SGC got its hands on it, hardly anything about the place was familiar.
But McKay looked oddly put off by that, and not in a good way. Both soldiers watched him for a long, tense moment as he stared at the equations before him; finally, Sam stepped away from the empty space on board number six and handed him a marker – though, Jack noticed, it was a color she had never used.
He actually recognized the first line... but only because it was a direct copy of something Carter had written on the third board. Or maybe the fourth. Everything the man scrawled after that was complete and total gibberish. Greek, even.
But not to Carter. She watched the equations take form intently, and somewhere around the fifth or sixth line her mouth fell slack. He knew that expression, and it was never good. "Carter?"
"I hadn't considered that," she said softly.
"Considered what?"
"That the amount of extra entropy generated would be proportional to the distance between the two realities."
Of course it would. "In English, Carter," he pressed.
Her eyes, when they raised to his, were troubled. "Since this reality is much further removed from ours, we can't really use what happened to Doctor Carter as a gauge for what will happen to us. It will be quicker this time. And worse."
She always had known how to kill a party, he thought as the implications of that settled in. "So... theoretically," Jack said, "someday we could bounce in on a reality so far from ours that we just immediately spontaneously combust?" The idea was kind of cool, in a horrific kind of way.
"I doubt there would be fire involved, sir."
He shot her a look, and she sighed.
"Okay. Theoretically, yes. But realistically, no."
"Why not?" McKay asked.
"Yeah! Why not?"
"Because any reality that far diverged wouldn't have us in it. And we already know that an alternate won't suffer the effects if their counterpart is dead."
"Ever? You know that for sure?" the other scientist asked.
"Well, no. But it certainly doesn't affect them as soon, at least."
"Then it's possible that the colonel is correct. There could, in fact, be realities different enough to induce that kind of failure, even if the problem of duplication wasn't an issue."
Jack put up a victory sign. There was nothing better than being right. Most of the time.
"But-"
Any further technobabble was blissfully cut off by Jacob's arrival. "Sam," he beckoned softly. "There's something I think you'd want to see."