My friend that taught the class said that most officers that get into high stress situations will have a heart rate of over 200 bpm. He says that when he trains guys to do this his goal is to get them to have normal heart beat in high stress situations.I think you should go play paintball so you know what fear does to you.
Your first plan should be to escape and evade. Good cardio, constantly "scanning and focusing", and paying attention to your "spider sense". You can use simple excuses at work by saying "need a bio break" or when going to the store "forgot my wallet in the car". If you're out and about you can say "dog wasn't feeling well".
I will say that police officers are what make me the most nervous. The overwhelming majority are Barney Fife.
He is SWAT trained and instructor. He teaches self defense, Krav Magra Israeli defense forces style fighting. He says there are plenty of guys throughout different dept. that mostly rely on their weapons that they have on them and the minimal training required. He says he really works to get more guys highly trained. Physical and mentally prepared for every kind of situation.