There's one person you can go to, when your life sucks enough that you're ready to throw away everything about it in favor of something else. Such as, for example, if you get into a terrible fight with your father and he wrecks all your possessions that matter and demands you be kept under constant guard, even if it's just by your other family members (who are also all the actual worst).
There's one person in Cyllene's family who isn't the actual worst, and quite conveniently it's the same one.
The witch runs a hand through his hair. "You sure about this, kiddo? I mean I'm all for sticking it to the man, but if anything's not how you like it you won't exactly be able to drift back to me and complain."
"Uncle. Please. I'll be fine - or I won't; little matter. I at least won't be here. I'd take my chances if you'll let me."
"Yeah no sure, I gotcha covered. You know I've gotta check, though. Last call to bail out?"
"I would say it was almost as if you hadn't known me since hatching, if the category's competition weren't so dismal."
He laughs at that, without much humor. "Fair enough."
As it turns out, Cyllene ends up with several more opportunities to back out; figuring out how to order the spells is a small nightmare. They have to do her legs and her lungs at the same time (and given the situation the two of them can hardly go up to the surface), but the language spell takes long enough that she would probably drown if they started there. Under different circumstances it would be easiest to do language comprehension first, but the other two spells both require the use of her voice. Ultimately the witch gives up and detours to find an air-creation spell, and Cyllene sings until she chokes and sticks her head into a little pocket at the top of the cave, treading water with her strange-wonderful-marvelous-perfect - but somewhat difficult - legs (legs legs legs legs legs!!!). Her newly-webless hands aren't much help, sliding so frictionlessly through the water, but there's a little crevice in the rock where she can stick just two fingers, and by pressing her other hand in a different spot she can balance with her face in the air without needing very coordinated kicking from her confounding and delightful new limbs.
She runs her tongue over dull, rounded teeth while her uncle busies himself with the next set of preparations.
"You're real lucky we're pals, Llene," he sighs, and pulls out some ludicrously powerful little trinket which will allow her to sing two spells at technically the same moment, in some kind of time loop that Cyllene doesn't need to know the theory for to take advantage of. The tunes clash and the tempos don't match at all but she's good at music and it doesn't matter that there's another Cyllene trying to pull her wildly off-key; she can hold her own line regardless.
Her voice - or voices- go out and for a moment she's terrified, that she's human and omniglottal but still here, that now she's not even stuck with forced supervision but stuck in this tiny crack of air - even if her father were agreeable she just wouldn't have time to make it to the surface alive - but then the tips of her fingers and toes start dissolving.
It is not comfortable, and it's in fact dread- and horror-inducingly not-comfortable; she tries to start screaming - but right, no voice - her grip falls away and she thrashes back into the water - there's a hand on her shoulder for the remainder of time her shoulder exists, a few seconds - and then there's nothing, she's nothing.
But only for a moment.