Another article specifies that she had a knife:
http://www.sfgate.com/bayarea/article/Woman-18-shot-dead-by-San-Mateo-sheriff-s-deputy-5527706.php
My beef with this incident is that her family called 911 for what was clearly a medical issue, and the responders sent armed police instead. If they clearly specified on the 911 call that this was a medical issue, there should not have been a need for an armed police response to a private residence.
I guess I would need to hear what was said on the 911 call.
Generally family/staff are in a better position to talk someone down but occasionally things go bad fast and the cops have to step in. Some of these individuals are in a place bad enough that they should never have been released from the institution they were in. Some of these folks are high functioning enough to engage in these types of acts in an effort to try to game the system into getting them a relocation or different treatment and can go far too far in their plan. In these situations the family staff are of no help.
I have managed a location that had 38(?) of these types of clients living in apartments and I have far too much experience dodging flying feces and being chased by people with butcher knives. Under normal circumstances these situations could be brought to some type of successful conclusion by staff and documented appropriately for the clients physicians and counseling team to address but, in those rare situations when someone in this type of state eloped from the program or targeted another client, then the situation is not handled as a medical issue by the emergency response community, rather the situation is always considered a public safety concern first.