It’s not physical damage to her brain. She has schizophrenia and developed symptoms of it at an abnormally young age. She didn’t have a clear grasp on what was and wasn’t real and that ultimately led her to stab her friend nineteen times. It’s clearly a condition that has presented itself as very dangerous for her, and it needs to be under control before she can be released.
For me it’s, “I shouldn’t be doing this. I’ll never find it again. This is an awful place to put this,” as I commit to setting something down in the abyss.