I just listened to the Met radio broadcast of Dialogues of the Carmelites and I have to say: WHOA. Look, I know how it ends. I have seen it live (with a friend as one of the sisters). But listening to the final scene, with no visual cues, was its own kind of terrifying. Perhaps because I do not know the piece well (having only seen/heard it that once), not knowing when the guillotine slices are coming was just...well I gasped aloud every time and my cielo became worried. The first time, I actually jumped I was so startled. Poulenc was a genius for sure. I am still shaking and it has been over now about half an hour!
Here is the final scene, from an earlier performance (in the 80s) of this same production. Close your eyes and just listen.