An escalator in a Hong Kong shopping mall packed with people suddenly went in reverse which sent people falling all over. 18 people were injured when the stairs went from up to down. That is the worst scenario in my mind, gravity has a bigger pull downward.
Hong Kong police arrested two mechanics after concluding that this was done on purpose. There is a video from this mall showing this incident as it happened and this was one big escalator.
We humans are coming up with more and more unexpected ways to hurt other people every day.