My favorite bit of Kenneth Branagh’s delightful film, A Midwinter’s Tale, is when one of the (not very professional) actors confesses that whenever he forgets a line or what he’s supposed to do, he says, “Crouch we here awhile and lurk.” And then crouches behind something and waits. I do not think this line exists anywhere in the canon – at least not exactly – but I do so love it.
And it DOES sound a great deal like “Couch we awhile, and mark.”
And one could use it for just such an eventuality just as easily.