happened to me (again) quite recently. was at a posh party and while chatting with the host on the sun deck (constructed of wooden planks with gaps), i stepped back and the heel of the shoe on that leg sank into a gap. trying to maintain balance, i stepped back with the other leg and the other heel promptly sank in ie. both heels stuck in the gaps

the heels were stuck so tight the host had to bend down to help yank my shoes out.

i was so embarassed