He starts fiddling with the controls again.
She doesn't purposefully cause it to explode again; while it was funny, she considers this an Unwanted Side Effect. She's trying to do a thing, and that thing is not 'cause various hilarious explosions.' She will make pretty things, damn it.
She continues making pretty things. If she twists the magnetic field just so and stretches it out like this she can get it to make little arches, and then if she turns down the gravity generator responsible for keeping the thing mostly weightless just a little she can pull those parts down far enough that she can turn the zero-g back off with the pattern still intact, and if she arranges magnetic fields like so the liquid makes little spiky bits on this part that can look sufficiently lace-like to match her specifications, and...
Was there an outside world besides this fascinating machine? She forgets.
Except... one of them is going noticeably faster than the other, and after a few loops they collide, knocking themselves out of the air. One is recaptured by a different set of magnets and the other one falls on the floor.
This gives him an Idea.
He sets up the endless loop again just because he can, and then he tries to figure out how to turn the rest of the contraption into a racetrack.
She starts on a third, convinced that while this one might not be perfect, it might look something like what she's trying to achieve instead of not.
A few minutes of careful construction and testing later, he has two long near-identical courses spiraling down and then up again from two adjacent entry points controlled from the same station. If they're truly identical, the balls will collide in midair, up near the top of the contraption; if one course gives better acceleration than the other, the winner will pass through that space first; and either way, both balls will hopefully be caught by the leftover contraption elements he set up for that purpose, but he can't be sure they won't fall on the floor until he tries it.
He releases his racers simultaneously into their respective tracks.
They pick up speed pretty fast - he thinks he might have underestimated how much acceleration they're getting from those long curving sections. In fact he's now kind of worried that—
CRACK. CRACK.
Miles makes enough semirandom changes to scramble his racetrack-railgun past recovery as quickly as possible, and then he steps away from the contraption's enclosure, which now has two spectacular spiderwebbing cracks in its glass walls, up high on opposite sides of the enormous cylinder.
Either way, she's pleased with her third result. She's just finishing up the final touches of it, coaxing geometrically perfect spirals into something more organic when a very loud something startles her out of her fugue.
She looks up in alarm at the loud noises. She notes the cracks in the contraption's enclosure.
".... Um, Miles?"
"Hi, Yvette," he says, and is briefly distracted by her ferrofluid lace. "...That's amazing, first of all, and second of all I think we should go look at another exhibit now."
Then she looks at the contraption again. "And - yes, yes, let us. Go look at another exhibit now. Molecular biology?"
"Let's go learn about molecular biology," he agrees firmly.
Yvette kind of would like to ask how the hell he even managed to do that, but she suspects he might like to just never talk about it again.
The molecular biology exhibit seems like it might be less wildly oversimplified than the wormholes exhibit, but Miles doesn't know a thing about molecular biology so he has no good way to tell for sure.
"This museum is very good at making everything pretty and approachable," she observes.
"It is," he agrees. "Although they could stand to increase the safety standards on their interactive exhibits."
"How did you even manage that, anyway?"
".... You made a railgun out of the exhibit? The exhibit could be made into a railgun?!"
"Not on purpose! But I mean, the exhibit basically is a railgun, just an unusually complicated one that is unusually bad at accelerating projectiles. As an interactive kinetic sculpture it is both interesting and educational, and I can't fault them for including it. I suspect I was taking advantage of unintended behaviour when I constructed my racetrack."
"I mean, following the basic principles of a railgun and being a railgun are different things."
"Well, yes, but I don't just mean that the principles are the same. It's... I'm having trouble thinking of a good analogy, but on a conceptual and physical level they have a real equivalence, even though the exhibit wasn't intended to function as a railgun per se and in fact is still pretty bad at it even after I got it to try. If it had been much better at being a railgun, it would've done more than just crack the glass. I joke about their safety standards, but I'm actually pretty impressed - they clearly hadn't predicted that anyone could do what I did, but the enclosure stood up to it anyway."
"Huh. Well, I'm glad the enclosure stood up, anyway. I'm having visions of shattered glass everywhere."
"Railguns that are good at being railguns are up there among the most efficient ways to propel a kinetic projectile, so yeah, um, it could've been pretty bad. Hooray for high safety standards?"
"High safety standards are great. They prevent me from causing catastrophic accidents."
(This actually gets an amused snort out of Miles's bodyguard, who has been spending this entire time being patiently watchful and unobtrusive.)
Yvette giggles. "Notice to all Betans and people that build things. 'High safety standards so Miles doesn't cause catastrophic accidents.'"