I have assaulted many times by my clients..First assess the situation,then try to talk to them and tell them you are safe and you are loved,maybe we can and talk if not wait till he calms down for staff safety,initially they are only after one person who they thought have done them wrong in one capacity or another,so the one staff that isnt the target should observe making sure no one gets hurt,the other staff that is being challenged, should be in reach if something happens otherwise find safety and wait it out,then when it is done staff clean up mess other staff call 911 if someone got hurt.