YANBU at all and it was really good to react as you did.
I had a really scary moment this morning when a small kid (about 7) on a bike flew into my path and we missed each other by about a second. Noone's fault, he was on a cycle path but my view blocked from someone as small as him by a parked car. I jumped out to make sure he was ok, as his dad was miles behind on the cycle path and dad and I had a civilsed chat and kid was ok but I think I might have nightmares tonight about what might have happened to him two seconds later.
one of those growing up things I guess for all of us.