It's not like it's that difficult to work out. Tell a young girl that she is here because otherwise she'll murder her family and she'll be horrified, angry, pleading. Tell her that her emotions are making it worse, that she's doing it on purpose, and she'll go hysteric.
Lock her up for that hysteria, in cold walls with cold people who don't talk to her, look at her, touch her, and of course she's not okay.
(Almost don't touch her. There was one man who liked to touch her, and she hurt him a lot, and she said, stubbornly, even when they panicked and hit her and took her food away for the night and locked her in the cold room, that she'd picked him for no reason. Even then she hated to seem weak. But he'd touched her hair, then her chest, her stomach, and then he'd slid his hand down to touch between her legs and the girl had unfrozen and hit him with most of the ceiling from that room and a chair leg which had gone right through his chest - )
That girl is not Wanda. Wanda loathes that little girl, plaintive and scared in the back of her mind, wanting her father and her brother and her life back and trying to be good enough and failing. Wanda thinks it's disgusting. Wanda would never beg, not even for her life. (Not for anyone else's, either.)
When she turned nine, on her birthday, the girl cried mutely to herself, because she and her brother were meant to be having a cake shaped like two dragons, because they both liked dragons, but her brother didn't love her anymore. This was the point where the quiet people, who had been trying to make her controlled enough for her father, despaired of any progress, as everything broke around the silent girl, and sent her to a new place.
In the new place, all was still. She could not move her hands, and they put her in a tight, white canvas coat which made her hug herself, and bound her onto a wooden frame so that she couldn't move her hands. Twice a day, in this place, someone came and did not look at her eyes, feeding her with a spoon. She was allowed, with her hands taped and splinted, to move around the room, but for that she had to be gagged as well, so that she would not rip at the tape with her teeth.
As she walked, back and forth endlessly, in that room, her legs got stronger, so she started to run back and forth, this furious loping movement like a big cat in a small cage.
And misery turned to anger, in leaps and starts.
She would be like this forever, but she refused, because the man who had put her here had to die, had to pay.
This was the birth of Wanda.
Now the crying, and the misery, and the desperation... she labels it all as crazy, weakness, and all she can do when it rises up is get angry. She wakes from nightmares, shaking and trying not to throw up from the hard heavy lump of terror in her stomach, so she thrashes and rages instead, dark hair falling into dark eyes, impossibly angry, so angry that it seems like anyone else would ignite from the sheer force of vitriol and hate in her.
It festers and it festers and every time she wants to die from it all, she reminds herself that it was Magnus who did this to her. She nurtures it, the mother to an impossible hate, and makes herself so angry that she throws up sometimes.
She wakes up shaking and crying some nights, and fights that down, compresses it into rage until she can barely breathe for how full she feels with it, hot in her veins and tasting like blood where she bites her tongue and lips raw, thrashes like she's having a fit.
And it's fuel, for her. She wants to kill him. Even though - no, especially because he fathered her. There is not enough freedom to work to the ideal, but she runs and kicks and leaps, crouches, bolts along raised surfaces. She learns perfect balance, and she starts stretching herself as much as she can, doing exercises and limbering until she can twist her leg up, hook it behind her bound arms, and pull.
All it does is dislocate her shoulder and fracture her thigh as she falls, and she spends an hour gasping on the floor, fighting down the pain and letting it thicken to fury, before her guards realise that she's crying from pain.
She leaves that place, eventually, but she never escapes. It wakes her, in a house full of people she doesn't know and a brother who left her behind, and the hate swallows her. (And maybe there's a little bit of that girl left, who wants to keep them safe, but Wanda is trying to kill it.)