How would you act in front of  an act of bulling (bullying)?

Today I have (en español se dice he visto, pero en inglés sería mejor utilizar el pretérito)watched a video on Youtube that has shocked me a lot. In that video, two boys simulated a bulling (bullying) attack. One of them, was the agressor and bullied the other asking him for some papers. They represented this scene (acted this scenario out) in front of some people to analyze their reaction.
In most of cases, people ran away and simply they made (pretended)as if nothing was (were )happening. (What is most surpring)for me is that the few people who decided to act, were women.
What is happening to us? I know it is difficult to answer this question and depending of (on)the scene I am not sure about my reaction. Our natural instinct tends to protect ourselves but if we do nothing there is created a very unfair situation. If the person attacked was (had been)me, what (how)would I feel if everybody crosses near me (just passed by)as if I didn't exist.

Here you have the video. Watch it and take (make)your own conclusions.

http://vod.io/NB~r6/