When I took UNIX classes in college, I had a knee deep pile of textbooks. My SIL took a UNIX course while he was working towards his cyber security degree. His textbook, note that is singular while mine was a mountain, was tantamount to cliff notes!
Years ago I had a crew doing a dig on Clay Street in San Francisco. I noticed 4 very serious looking dudes with SBRs patrolling a nearby property. A "friendly competitor" of mine saw my Suburban and decided to stop by to see what my crew was up to. As we were talking, I told him about the dudes...
It is all too easy to armchair quarterback this type of situation, so I will try not to do so. What I can say is if it was my family or friend the "Peacekeeper" killed, I would want that person to suffer dire consequences. Although well intentioned, the "Peacekeeper" f'd up.