Before I can get down to the theory, I must give an example of it in a different work.
In the DC elseworlds franchise Injustice, the plot is kicked off when the Joker, using a combination of Kryptonite, and Scarecrow's fear toxin, tricks Superman into killing Lois Lane and her unborn child. And not only that, but he also hid a nuke in Metropolis and rigged it to go off if Lois heart stopped beating. Needless to say, Superman is not happy about this. Grief stricken, Superman kills the Joker and decides that inspiring hope and showing mercy to villains is not enough. He needs to stop crime BEFORE it happens, and make sure that Supervillains never get out of prison.
And he's not alone, half of the Justice League, and other DC heroes not affiliated with the League decide that Superman is right, having lost friends and loved ones of their own in Metropolis. But another group of heroes, consisting of the other half of the Justice League, and other DC heroes not affiliated with the League, and lead by Batman, believe that this will turn Superheroes into the villains they fight against. Initially the two sides try to remain on good terms, but as Batman continues to refuse to execute Supervillains deemed "too dangerous", or get involved in forcing warring nations to stand down, the Justice League splits and start submitting to their darker instincts, silence the few voices of reason in their teams, and blindly follow either Batman or Superman to the edge of the moral event horizon as the DC universe breaks out into civil war.
But it turns out, this was Joker's plan, to corrupt the DC heroes and get them to turn on each other.
What if Alastor's goal is the same thing? To make sure that the hotel fails to show Charlie that he and Lucifer are right, then betray Charlie so that when Charlie kills him, she will no longer trust anyone or believe in redemption anymore, turning her evil. How could the Princess manage to avoid this trap? Or would the other characters have to snap her back to her senses? Or what if they were also corrupted?