Back in the day, in middle school, one of the really cool things was to give your friend a "flat tire" - step on the heel of their shoe while they are walking (or even better - running) so their foot comes out of the shoe. Sometimes it would only have the heel of their foot pop out, but if you had a really "good one" and they were running, the shoe would come flying off their foot. I once saw someone's shoe go flying over their head and land in front of them.
Maybe that happened here?
