A fart that slips out while taking a leak at the urinal or forcing a poop in a stall. This is usually accompanied by a sudden wave of embarrassment.
If you release an escapee, do not acknowledge it. Pretend it did not happen. If you are standing next to the farter in the urinal, pretend you did not hear it. No one likes an escapee. It is uncomfortable for all involved. Making a joke or laughing makes both parties feel uneasy. "Dude, I just let out an escapee!"