At times like this and others I believe we must consider the "toality of the situation as we understand it ", but realize we may not know all that is going on. There are just so many factors that go into how we should respond to a given situation that it is difficult at best to give a concrete response. I do subscribe to calling the authoities immediatly and being the best possible witness you can be. This I would do without hesitation as earliest it is safe to do so. However our individual response will need to vary. If I am with other 5 blackbelts from my dojo and were walking out of the local gun club to witness an assault in progress will bring out a different respose if I am unarmed (not good) and with loved ones to see several people attacking an other with a knife or in a shootring situation. I realize these are two extremes and most fall somewhere in between. But we should not forget our responsibility we have to our own family to come home each night. As for rendering Aid to a victim, having been in EMS for over 20 years I would do so as soon as there was no immediate threat.