Sort of an anti-catharsis, whereby insight or clarity is achieved through tragedy or disaster? The moment Hamlet realizes his uncle was behind his father’s murder; Raskolnikov’s crime and eventual confession; everything Cormac McCarthy has ever written. Is there a word for these moments, these horrible revelations or insights?
"Epinfamy" is the best neologism suggested by a Cowen commenter. But another points to a real word:
Anagnorisis -- a revelation into the true nature of things, usually through tragedy. We could broaden the technical, literary meaning of anagnorisis to include the truth that is revealed, not just to the tragic protagonist, but also to the readers. There is a classic poem by Aeschylus that expresses insight through horror:
"He who learns must suffer. And even in our sleep pain that cannot forget falls, drop by drop, upon the heart, and in our own despair, against our will, comes wisdom to us by the awful grace of God."