I have a similar story. When I was a cop I went to a domestic dispute where one of the family members was brandishing a knife. I drew my gun and ordered a young man to put the knife down. I stated about a half dozen time “Sir, please drop the knife"..."Sir, please put the knife down’...over and over with all of the niceties that a police officer is trained to say. Well, it became apparent that the idiot did not want to put the knife down. By all rights, I could have shot the jerk. Finally, I told this guy to “Put the fucking knife down or I will kill you.” Well, this seemed to at least get his attention as he did drop one of his knives (He was still palming another one I found out shortly). When all was said and done, he and his family filed a formal complaint against me for all kinds of things I did not do. In the end, I was cleared of every charge except one. You guessed it...swearing at a civilian. I stated that politeness did not work and that I needed to change my strategy to convey to this guy that if he did not put the knife down it would be a serious consequence for him. I went on to explain that I needed to resort to a language he fully understood and the seriousness of his action and that saying please and sir were not getting me anywhere. I had to put “strength” in my voice that gave him the message that I was serious about having to kill him if he did not comply. Anyway, I went through all of the niceties of an IA investigation and got a letter in my file and all future employers now know that I swear from time to time.
I should have just shot the fucker and have been done with it.