Well, perhaps one of the most logical scenes to start examining is the scene where Sheila starts ripping eyeballs out of a goldfish's face. What does it say about the novel's intention that Torey doesn't immediately give in to the tempting response of horror and disgust, and perhaps contempt? Perhaps the suggestion is that Sheila is trying to excuse herself from Torey's influence by immediately trying to offend her into mistreating Sheila.
But why should Sheila desire that negative attention? The answer lies in the horror she experiences at home. The behavior suggests that Sheila is chronically paranoid about explosive situations, so instead of allowing the stress of paranoia, she immediately acts as a catalyst, even though it is masochistic and sadistic to do so. The masochism comes from the intense loneliness and horror she endures without a friend in the world, and the sadism is demonstrated in her aversion to Torey's attention, and also in her maniacal decision to harm a living animal.
By removing the eyes of the fish, she suggests that there is something about vision that she doesn't quite have peace with. Is it that she doesn't like to be watched? That certainly follows, because as Torey discovers, Sheila has received a lot of negative attention. Perhaps it is her way of warning Torey not to guard her. Sheila is saying, "Don't look at me." But the reason behind this aversion is that her uncle has sexually abused her throughout her life, and in one instance, he even performs a torturous genital mutilation on the young child. Of course she doesn't want any unnecessary attention. She wants love.
Ultimately, Torey cannot save Sheila. She can't even really be an asset to her. Her role as an employee prevents her from adopting these case children every time one of them has a horrific home life—the unfortunate reality of Torey's life is that, although most people don't have to think about these things, she does. But, Sheila is finally given the gift of confidence through Torey's patience, and when Sheila tells her story to Torey, that is a healing endeavor.
