While I agree that suddenly forcing her to go on the escalator with no support is not a good idea, please work on this with her. Use a gradual approach to desensitize her--for instance, first look at pics of escalators, then watch YouTube videos, then watch peopl on them but don't get on, then ride a small one, etc. Push her just to the point of being a little worried every time and praise her a lot each time she succeeds. I spek from experience as an adult just getting over a truly bothersome and inconvenient phobia. My parents allowed me to avoid my fear for decades. It was absolutely the wrong approach and impaired me in my adult life.
She really enjoyed where they went and wants to return, so we will probably get an annual membership for the family and will have lots of opportunities to practice.
