its thr g-force i think, it may not be much but just a couple could make ppl faint if they aint use to it. especially when they scream lack of oxygen don't help.
Why the poor girl in the first clip is on the ride is a mystery to me. I suspect if her boyfriend has forced her to join him, he won't be her boyfriend for long. That, or there is a seriously unhealthy dynamic between her and him and she is behaving much like many woman who are being abused behave, maintaining fidelity to a man who is cruel and hurtful to her. My hope is that she ditched the heartless ass who laughed while she wept and screamed.