Their piece has no safe square, but you don't trap it
A piece deep in your territory, no retreat, surrounded. You let it escape because you don't see how close it is to dying. Or your own piece gets trapped and you didn't notice.
vs game: black queen on a4, white had a pawn push that left it with no squares. Missed.
vs puzzle: a bishop deep in enemy territory, one quiet move cuts off the diagonal and wins it.