Hmm...

This idea is [i]very[/i] experimental, but I was thinking, and here's what I have so far:

A teen with schizophrenia who gets shrunken down with the others, as you brought up already. However, due to some magic hoo ha which probably has to do with a whole lot of dead souls of faeries powering the machine, the teen's schizophrenia, over the RP, will become more and more sentient, eventually becoming my extra character and getting a body of their own(?). Another idea is that the teen unlocking their powers makes this slowly happen.

If you're worried about how I would handle this concept, I have schizophrenia myself, and will probably base the teen's schizophrenia and their experience with it on my own. If you still refuse it, however, I'm perfectly fine with that! This is just an idea in my head that won't go away, that's all. :')

Oh, and also, I can give you some information about schizophrenia if you're unfamiliar with/know little about the mental illness! :D