Nightmare scenario for everyone involved. Deep condolences to those affected.
In the time that I worked attractions at UOR, those kinds of medical emergencies, especially situations this intense, were brought up in training; but very rarely in-depth, and only to the extent to where you'd be able to call Health Services / Security in the moment. UOTM Attractions staff aren't lifeguards or medical staff, and they aren't trained as such. There certainly weren't enacted drills or training exercises on how to deal with traumatic events like this in the moment. This was likely the first time anyone on that team had dealt with a situation like this.
We have also been speaking for awhile on these boards of understaffing across the resort. I would bet that a number of these Epic TMs are likely new to the company, and everyone on staff is less than a year into their roles given the park hasn't been open more than half a year.
Does this excuse any actions from the TMs? I don't really care about that if I'm honest. Simply trying to provide context from my previous experiences.