Sorry you had such an unpleasant experience, citoyen. I have been involved in two collisions over 40 years where I needed hospital treatment and one where I was a witness cycling by, and, if, I'm honest, in those moments immediately after the collision, the one where I was the witness was the most confusing and distressing. Being the victim, provided, you are not so badly injured you are incapacitated, the adrenalin powering through simplifies everything. I just wanted to go home, I don't remember getting upset or feeling pain ( not at the time, anyway, later tons of it!). But the accident I witnessed did distress me, I wasn't sure what to do for the best, felt confused, worried, felt I should have remembered the car number, but couldn't ( it wad a hit and run) and very, very, angry with the car driver. Just sat and talked about rubbish to the guy till the ambulance came. Horrible and still feel bad about it for some reason, when I think of it. But my own collisions, once I was healed up, ( and that was a pain, if I'm honest) just felt a great sense of relief ( as both could have ended worse) and happy to be back on the road. I can quite understand why you got arsey with the driver, I would probably have done the same if he had bothered to
hang around.
You stopped. You showed you cared about another person in trouble. And if it was necessary, you would have done anything you were asked, I am certain.