Lace fabric, soaked from an earlier scene, had been left to dry. During a break, Prideaux picked it up and threw it down by the pool, casually. That’s when the light struck it. Everything clicked.
“It was like a kind of like lightning bolt… the light just hit it perfectly and I was like, my god, like that’s the shot. Like that’s the water, that’s the flood… the symbology of the flood. This is it.”