I don't see how some people have a problem with this?!
I think some of you may be imagining the FAs racing down the aisle like in chariots.
I am sure the reality, was, like normally when the push the duty free cart, it goes quite slowly, its just instead of the FA at the front just holding the magazine up, she was actually sat on the cart.
Those carts are pretty heavy to push, especially with an FA on, so I doubt it was going very fast. Only injury issue I see here is from the other FA pushing such a heavy cart. . .