I Just Witnessed

I just witnessed a nasty, nasty wreck in midtown. I was sitting behind a large SUV waiting to turn left. Another smaller car like a Avalon or such was facing the SUV wanting to turn his left. I saw the smaller car begin to try to inch to turn left and so I instinctively looked in my rear view mirror and saw a Tahoe or Suburban hauling ass on the right side lane. I started yelling, "NO, NO, NO!" and waved my hands but there was nothing that could be done. The impact was massive and it spun the smaller car completely around and when it stopped all kinds of fluids were running out of the car and the whole front was smashed. A man from a side street ran quickly to the smaller car and opened the door. An elderly man was sitting there dazed and the airbag was deployed. I looked to my right and the Tahoe/Suburban had been hurled into a yard where it had smashed into a small tree and then a house. I drove on through because there were tons of people jumping out of cars at that time that could help. In the other car the driver was sitting in the seat with the airbag deployed and was obviously unconscious to the point I could not tell if it was a man or a woman as the head was back. I was terribly shaken and called The Hubby to tell him to not go that way home and he yelled that someone should have stayed to tell the police what had happened. I felt that was directed towards me. There were lots of other cars/people there that had witnessed the accident and I didn't see the need to stay and back up more traffic. I was torn about what to do but I didn't need The Hubby yelling. Maybe I should have stayed but I just didn't know. That is one of the first accidents I have ever witnessed. Was I bad for not jumping out and assisting? Was it my duty as a bystander to get involved? Granted I was a witness but there were other people. Now I feel horrible for not staying. I just don't know what was right. My philosophy is to move the traffic on. Too many people can muck up things, rubber-necking and all but I was a witness. I just don't know. I told The Hubby that even if the Tahoe was not speeding it was going to be a nasty wreck because it was just inevitable by the way the scenario was laid out. Not good. The moral of this is NEVER, EVER, if you are in that situation turn if you are the smaller car, it can never be good, just wait.