There may not be a legal duty, but there is definitely societal expectation. For example take Scot Peterson the Parkland officer who has been blasted, called a

There may not be a legal duty, but there is definitely societal expectation. For example take Scot Peterson the Parkland officer who has been blasted, called a coward, and forced to retire for not confronting the Parkland shooter. https://www.nbcnews.com/news/us-news/parkland-officer-scot-peterson-s-message-families-i-m-sorry-n879716 https://www.nbcnews.com/news/us-news/parkland-officer-scot-p... If a police officer or department develops a reputation of running from danger, there are going to be at least societal consequences for them.