it can't unhappen

The Cliffs of Mistake

To know you're making a mistake as
you make it, yet not be able to stop,
is to step off a cliff, expecting to scramble
backward and up through the air to stand
on the outcrop you stepped from,
even though it can't unhappen as you
backpeddle wildly with the second step,
looking far, far below into the moraine
of pain you anticipate later, which is now
only the shock of recognizing the result
there's no leaping back from.
Oh God, and this is only a metaphor.
Might this be what metaphors are for?
To say what it's like before you hit what it is.

[Molly Peacock, in The Second Blush]