I almost went a over t the other day when, exiting the TST MTR station during rush hour, a woman with a pre-teen stopped dead at the top of the escalator in front of me and bent down to tie the child's shoe-lace....and I'm not even going to mention what happened behind me as at least four steps with two people on each came to a dead stop. Only with some pretty nifty footwork did I get away without injury and luckily in trying to get past her I managed to move her sideways and create a channel for those behind.
Ta ma de came in handy right then!