I watched the video and have to give her a break on this - I have been in places where worn stone is slick as ice. You can see she steps on the parts that are eroded and apparently had the wrong shoes. Some lowly personal assistant will probably be fired.
Looks like she picked up some monkey crap on her shoe to me. So used to wading thru shi* that she didn't even notice.
Then how come others weren’t falling ?