Or we could, I don't know, maybe try to treat her? I would rather live in a world where we treated all mentally ill people, even dangerous ones, with compassion than one where we just lock them up and throw away the key. I personally think that we, as a society, have a moral responsibility to lift each other up, but even if you look at it from a selfish point of view, it still makes sense. For example, it's possible that someday, you might have a mental break, maybe due to a tragic event or brutal experience, and will need help and wouldn't you rather be treated kindly rather than being locked away and forgotten about?