The opera's last scene is riveting. The nuns sing Poulenc's "Salve Regina" as they are executed. The staging does not show an actual execution; rather, the nuns sing loosely grouped on stage, and at each sound of a guillotine blade falling, a nun stops singing and drops to the floor. Finally, with only the prioress and a novice singing the piece as a duet, the prioress is executed. Then the novice sings alone briefly, and she drops as she is executed. Then there is silence.
It's an amazing and moving scene.