Vertigo's ties up its story in a brutal sequence followed by a very ambiguous ending. We'd shout "Spoiler alert!" but we know you've watched this film diligently at least twice and are reading this learning guide just to deepen your understanding. Right? Anyway, after Scottie finishes confronting Judy, a nun suddenly appears, prompting Judy to fall from the same tower window that "Madeleine" (really Elster's murdered wife) jumped from before. All we see in the last frame is Scottie staring down in shock and despair.
Why leave audiences feeling so perplexed? As a thought experiment, think about how much less powerful Vertigo would be if it ended more conclusively. Left as it is, it leaves us with a vertiginous hangover. Like Scottie, we're compelled to keep returning to "the scene of the crime" to figure it out.