Sounds as though the cops did a fine job.
Law enforcement did what they were trained and hired to do. They have done nothing wrong. The nut job, however, broke several state, federal, and moral laws. She did a lot wrong. She faced the consequences of her actions, schizophrenia or other wise. The vast majority of schizos do not kidnapp, slash/stab, and kill people. They mostly just use their cars as trash cans and sit around smoking pot. So she definitely jumped the shark in her decision making.