You just reminded me of an incident with an old flatmate. I used to live across the road from a major train station. I was crossing the very busy road to my house when a homeless man stumbled, fell and broke his skull on the pavement. He was lying there on the footpath with blood pouring out of his ears and people were literally stepping over him and completely ignoring the fact that he was severely injured. I ran back through 4 lanes of traffic, called an ambulance and was about to do CPR when an off-duty cop ran up and took over, bless him. He was much better trained than me. My flatmate was astonished that I was going to do CPR on a heavily bleeding, drunk, smelly old homeless man. I asked him what the hell else should I have done, he was dying! Flatmate said, walk way, it wasn't your concern. JFC, I can't understand that at all. He remarked the man may have been HIV positive (which I had already thought of) and asked why would I risk it. I know it would have been a risk, but I wasn't just going to stand there and do nothing. I wouldn't have been able to live with myself. Even if nobody was prepared to do CPR which I totally understand, I don't get how nobody else even attempted to call an ambulance even though pretty much everyone carries a mobile phone. My flatmate's attitude shocked the hell out of me, but so did every single person who stepped over an obviously injured person. I lost my faith in humanity for a while after that.