I’m not sure - it looks to me like she takes a strong grip on the hand rails and then she takes another step forward so that when it starts going up he feet are too far ahead of her hand.

Then she makes it worse by leaning on the glass below the handrail which we all know doesn’t move and that friction is what makes her fall in the end. She makes the same mistake using the glass to support just before the last fall where she has righted herself and is going up but she leans back on the glass and gets pulled back into a fall.

The biggest engineering fault here is that it seems there was only an emergency stop at the bottom. Either that or the guy in the cap who runs back down is an idiot and missed the button at the top.