Hitting your head hard

Poor Natasha Richardson. My sympathies to her illustrious thespian family.
Her story reminds me of something I witnessed recently and now I am mortified about.
I went ice skating at the rink in the Houston Galleria shopping mall a couple of months ago. In this particular rink you skate at your own risk. There is nobody on the ice to keep order or give aid, which I think is extremely wrong. The rink was almost empty, but as is usual with skating rinks, there were several groups of people who had never skated on ice before. There was a small group of Latino kids who were hanging from each other for dear life. They were all very annoying, as teenagers always are. This slightly chunky girl kept falling over and over. She was hopeless. They were all laughing their heads off. At one point, this girl fell head first onto the ice. She hit herself hard on the back of the head. It sounded like a wrecking ball hitting concrete; a thump so loud and sharp and dry, it made my own skull hurt. I could tell it hurt a lot, from her trying to save face while rubbing the spot, but they were all laughing like idiots, and she seemed to be fine. She was trying to laugh too. A few seconds later, she was back on her feet again, looking normal.
Today I'm thinking, first, I should have asked her if she was okay. Second, I should have told her to go to first aid and have her head checked. I hope she is not dead or in a coma.
And from now on, I'm wearing that stupid helmet when I bike.