On the moment of expression

I have, of late, been trying to articulate a concept in being/zen/creativity that I'm keen to interrogate further in my creative practice. It's to do with allowing something to build until the perfect moment of expression - a notion repeatedly espoused to me during drama school and other artistic pursuits - but if there's a succinct word or phrase to express it, I cannot for the life of me remember it.

The closest I've been able to get to it is this phrase in the introduction to Anne Bogart's A Director Prepares:

A scuba diver lies first in the water and waits until the entire ocean floor below starts to teem with life. Then the swimmer begins to move. This is how I study. I listen until there is movement and then I begin to swim.

I'd love to hear if anyone has any inklings about the origins of this concept, or at least point the finger at the moon.