No. You're required to render what aid you safely can. You are not required to put yourself at risk. I'm not saying they themselves should have gone mano-a-mano with the attackers, but they could have shielded the poor guy, or gotten descriptions or any of a bunch of other options. Instead, they just munched their popcorn and watched these two poor guys get their asses kicked. And Adrian wants to tell me that Amsterdam is such a warm cheery place.