"Why didn't she just say that?" mutters Applejack, mostly to herself.

"If I could do that, I could just look into the future to see what next season's fashion trends will be, and then I'd have the trendiest boutique in Equestria!" says Rarity dreamily.

"But then you'd be setting the trends," says Fluttershy, "and if you do that, where did the trends come from in the first place?"

"Didn't you hear what Princess Celestia said? There isn't just one future, and the future you see isn't necessarily the future you end up in—no, wait, it can't be, it'd be like having a spell that tells you whether another spell stabilizes, Canter's argument should apply. She'd have to be seeing some other future where the trends were set the normal way." (Not that she has any idea what this is.)

"Then how is it any different when Discord does it?"

"You should ignore that. He's just messing with you."

"Isn't he always messing with us?"

"Yes, Rainbow Dash, it is rather the entire reason for my existence. But I'm feeling nice today, so I'll give you a hint: the puzzle would be almost the same even if I didn't have some of my more, ah, unique powers."

"—anyway, Applejack, how is it different when Discord does it? Or, no, it's not that it's Discord doing it, he said it would be the same without his powers, so it isn't that he can control which future he ends up in—there must be some limits to that, by the way, he can't end up in a future he's previously seen any more than anyone else can; chaos gods aren't immune to diagonalization—"

She thinks silently for a while.

"I've got nothing."

"This is a waste of time," says Rainbow Dash. "The Princess already said he couldn't control our choices."

—can't control their choices—chaos can't—

"—that's it!!"

"No one can control which future we end up in, but we're the same in every possible future! Discord doesn't have to have seen our particular future to be able to predict what we'll choose, he just has to have seen us, because we'll make the same choice every time we're in this situation! And that's why we can't just say 'well, the Elements are either in the vault or they're not' and ignore Discord's games, because then we would have made the same choice in whatever future Discord saw, and he would have stolen the Elements!"

"That kinda sounds to me like we're letting Discord control our choices after all."

"—no, no, no, no, no," she says, still giddy with epiphany. "It's not Discord controlling our choices, it's us! Versions of us from another timeline, or another universe, or something, but I think that's sometimes how it has to be—well, it doesn't have to, you could make all of your choices at random if you wanted, but then who would trust you?—"

"He makes all of his choices at random," she says, taking off again.

Applejack grabs her tail.

"Well, well, well," says Discord. "I guess we can't all be Lawful Good. Though I do admit I told a tiny little fib. The Elements aren't in the vault of Canterlot Tower. They're right here."

The little images of the Elements of Harmony in one of the stained-glass windows fall out of the window, and the real things clatter to the ground.

"You just can't use them on me until you've finished learning today's friendship lesson, got it?"

Meanwhile

Somewhere in the middle of Baby's First Decision Theory Lesson, Abrogail decides to get this over with and heads down to the hedge maze.

She trots up to where Discord, not impeded by a linear relationship to time, is waiting.

"What do you want?" she asks.

"I can't tell you that," says Discord. "That would be no fun. I think the more important question is, what do you want?"

She wants her fucking magic back. "You already know."

"I do, actually! You can have it, if you make it to the center of my labyrinth."

She's not actually enough of an idiot to trust this creature. "I'm the Lawful one here," she says. "How about you give me my magic back first, if you can even do that, and if you do, I'll do your stupid labyrinth."