I have ridden a horse like that as a favor for a friend. Friend was in cancer treatment and bought the horse for her mother. He was a gorgeous individual – but came from an auction in “before times” when there was no internet to easily sleuth.
Horse bolted out of the blue. No discernible triggers, just a mad dash with no regard for his personal safety. Thankfully we were in an indoor and I ran him into the wall. Me being a dummy and overly bold, I tried again. Trotting along quietly, then he did the same thing. Just blindly ran. No triggers at all.
I truly believe this is the most dangerous type of “disobedience/evasion/whathaveyou” since it is almost like they stop thinking – or reacting to any sort of barrier. I told friend he was definitely at the auction for a reason. I don’t know what became of him – but he was gone within days. I definitely agree that one shouldn’t mess with these, unless you want a pasture puff. Heartbreaking, I know.