I think this actually happened a while back.
Let's say you are a well known and respected pastor or church leader. You have taken a stance against something because of your religious beliefs. A group comes to protest your views at work (the church). They are carrying signs and make loud noises. You go out with a few of your fellow workers and politely ask them to leave. They become hostile and one person pulls out a test tube full of blood. He says this is blood from a person dieing of AIDS and threatens to throw it at you.
Question: Can you draw your weapon on that person? Is he threatening your life?