murray ....I agree.
However U.S does have a "gun culture" right or wrong, so get over it and on that basis, the deputy was employed to protect that particular community and almost by definition didn't do his job (allegedly).
A coward is someone who acts in a way to avoid danger to himself whilst employed in his duties and by that definition he is a coward.
What would I have done? No idea, probably run in the opposite direction BUT would have to accept the definition of cowardice.