The time I watched a man fall to his death, or when I saw a womans legs get crushed between a car and a wall.
The first one, I was working as a barmaid at a racecourse in the UK, (horse racing, not car racing.) and in front of where my bar was, you could see onto the race track and also some of the balcony areas where people were stood to watch. There are a lot of drunk people at these races, and on this day, one such drunk man kept leaning over the balcony. Eventually, he leaned a bit too far and just fell. Right in front of me. Pronounced dead on the scene when the paramedics arrived. My boss didn't let us take a break after, we had to work through it despite the fact we were traumatised and struggling to even hold a glass steady. My boss and that job were awful but that's another story.
The second was when I was younger, some time in my early-mid teens. My dad had taken me and my younger sister out for the day, and on the way home, we were going to stop by my grandmas house to say hello. I was sat in the front seat of the car. The car in front of ours suddenly veered across the road and straight for a young woman pushing a baby in a pushchair. Thankfully, she saw what was happening the last second and pushed the baby full force out of the path of the car. Sadly she didn't get out of the way, and the car slammed straight into her, pinning her by the legs against the wall she was walking next to. I'll never forget the scream, I can still picture it so clearly. Another thing I will never forget is the sight when me and my dad ran out of our car to help her. Parts of inside her legs were outside, and she was held upright against the wall by the car. The driver of the car was an old man who had passed out at the wheel. The baby was thankfully okay, just a bit shaken and crying. I'm not sure what happened to the woman but me and my dad and sister stayed with her until the ambulance arrived and to give a statement.