* CrowningMusicOfAwesome: Dr. Undershaft is in tears after hearing Agnes sing.
* ShockingSwerve: There isn't much buildup for TheReveal that [[spoiler: Salzella was murdering people as a second Ghost]], and [[spoiler: Salzella]]'s motivations do not make any sense whatsoever (he ''has'' been stealing lots of money, but that's more due to clever accounting than his antics as the Ghost). However, this is amidst characters saying that ''nothing'' in opera makes sense and it comes across as extraordinarily meta, especially with the scene mentioned under LampshadeHanging.
** It would seem that he was originally trying to frame [[spoiler:Walter]] for his actions to cover the tracks, and use the murders to do so, but getting badly carried away in the process.
** And the villain pretty much explains at the end that the murders were because the victims had found out his identity; the rat catcher was blackmailing him and the music director had seen him.
** And when asked why he didn't just leave the opera, as that would solve all his problems, he simply acts like that would be inconceivable, and doesn't get a chance to elaborate further.
** There ''is'' build-up to the fact that [[spoiler: Salzella]] is up to ''something'' that has to do with the accidents in the Opera House fairly early on (via internal monologue -- he compares milk going sour to the situation in the Opera House with the comment that Opera Houses unlike milk doesn't go sour on their own, and phrases it in such a way as to make it clear that ''he's'' the one making things go sour). Still not much, since it is a single easily missed line (there is more foreshadowing to there being [[spoiler: two Ghosts]], however).