Earlier quoted context omitted.
That's quite nonsensical, what you say. If she was there of her own volition, there would be no need for guards, and doors, and locks, and for people who took her away to have taken her away. She would just walked into the prison when she wanted on her own terms. (unlikely)
I believe empath means that unlike other prisoners, there's a clear and specific action she can take to leave prison any time she chooses to.
Someone making something you don't want conditional on something else you don't want either, does not make the situation voluntary.