Brave vs. Cowardly; Selfless vs. Self-seeking

I'm sickened by the Greyhound decapitation, but more disturbed by the elapsed time before fellow passengers came to the aid of the victim. What if it were me? What if it were you? Wouldn't you want several passengers to join together in your defense? Regardless of their ability, they could throw purses, cell phones, anything they have to startle the attacker before charging together. Of course, there is a high risk someone else would receive stabbing wounds, but how many of us would want our fellow passengers to organize and execute an evacuation before coming back onto the bus? Don't we all want others to be willing to risk injury so that we might not be killed?
Sometimes people wait a split seconds too long to see if someone else will step up, and in this case, one person on the bus instructed everyone to get off. What would have happened if that person had yelled, "Help! Fight him!" Likely the women and children would have exited the bus once awakening and realizing danger.
I've read other blog posts this morning and do concede that none of us know what we'd do unless we were in that specific situation. Given that, there will be many unique situations to come, and I'd like to have far more confidence in mankind that even if we do not know each other, we will come to each other's aid. I believe we must demonstrate an increased level of respect for all human life, both by not killing each other and by rendering aid, even in risky situations.