Bodycam footage, Female with a gun and mental illness

Former police officer confused about decisions bringing a health care worker to a gun fight. August 20, 2020, Phoenix Police receive a call of a woman, suffering from mental health, threatening to kill her boyfriend with a shotgun. Police attend the scene with a health care worker. Why? She is clearly arrestable for uttering threats; what is the purpose bringing the health care worker to a gun call. Suspect refuses to drop shotgun and gets shot by police. Non life threatening injuries. https://www.clintonjaws.com/