As a retired LEO (now doing something else) my reaction would depend upon whether my family was with me or not. If my family is with me I will get them out of harms way, no matter what. If I am alone however, my gut tells me I would probably look for cover and attempt to observe what is going on. If the situation turns into a stand off, and I have observed the suspect(s) the information may have benefit to the responding units. Doing this from cover however is the ONLY way to go.