Re: To help or not to help
Without having a duty to intervene, it is ALWAYS safer to step back and call 9-1-1 and be a good witness. The safer route isn't always the best route and sometimes a person has to take a stand on behalf of others. I think Janet hit in on the head with her comments about trusting your instincts. If you feel you can intervene successfully, you probably can. Remember, the bad guys have instincts too and if the hair on the back of their necks stand on end, you may have a successful resolution.
Choosing to intervene in a violent situation is truly choosing to lay your life on the line for someone else. That may sound dramatic, but you can die as a result. Firearms, knives, chemical sprays, clubs, martial arts training are all great tools, but the greatest weapon in your holster is your resolve to save someone regardless of the personal consequences.
Kevin mentioned sheep and wolves. Some are also sheep dogs. Kevin is a sheep dog on a global scale. I received my kibble for many years for tending a local flock and Its hard to turn that off. I honestly believe that Janet's comments are the most valuable here and if you trust your instincts in such a situation, your choice will be much easier.