You can't just look in black and white, guys. She might have given herself willingly, but now feels as if it was too much. I don't believe anyone can be THAT devoted, as to give themselves up to this entity whose real nature is still not clear to us. Minfilila wanted to help, and is helping Hydaelyn, but how much of the 'Minfilia' she kept is really hard to say. I got the impression she was quite full of sorrow, but we can only guess how Minfilia feels, if she still really is Minfilia. If she gave herself up to the crystal, and if her life force was absorbed in order to give Hydaelyn her voice back, Minfilia is no more. Unless we somehow make Hydaelyn stronger, the crystal will absorb more lives to keep herself alive, I'd wager.