Wow. You are quite the writer of the experience. Please, tell us more......
After you have met enough of these people, you develop a pretty good sense about what the wrong place at the wrong time entails and it ends up permanently in the back of your mind.
maybe 5 times out of 10, the violent event occurs in close proximity to a bar, typically around midnight. Alcohol and/or drugs are a very common component of most of the homicide traumas I have seen. I don't think I have ever met someone beaten, stabbed, knifed, or shot while walking out of the grocery store in broad day light. At night time, it's another story of course.
Situational awareness was drilled into us in the military and for good reason. It should be drilled into the heads of anyone who chooses to carry a firearm as it is far more likely to save your life than your ability to execute a combat roll. That combat roll was still pretty awesome though.