That def wasn’t instant death, but I do believe you pass out very quickly. People comment how people who commit suicide by heights might regret the decision halfway down, but here you can see she immediately regrets it.

As for how it feels, I read an article where a doctor said it’s likely you feel a tingle sensation. I would expect to feel horror and helplessness. More than likely it would be an extreme chokehold vs sleep apnea, because you’re applying your full body weight to the choke.

That last ditch effort to raise one hand I think is like when you move in your dream. She was likely already out and may have been dreaming she was hanging.