She was taking a break from tech rehearsals for the latest production of one of those shows, "Oratorio for Living Things," at the Signature Theatre. Inspired by, as she puts it, "the three Carls"-Sagan, Orff, and (Carlo) Rovelli-"Oratorio" is a musical meditation, for twelve singers, on time, memory, and what it means to be human on a turbulent planet at the edge of cataclysm.