[[WMG: [[PoisonOakEpilepticTrees Gustave was listening to his mother and the Phantom singing "Beneath The Moonless Sky"]].]]
And when he grows up, he will become one of Siegmund Freud's patients. The timeline seems fitting, too.

[[WMG: The musical was written to show what [[MisAimedFandom Phangirls]] are missing]]
The musical was actually designed to show ''why'' the Phantom and Christine can't be together and why it would be disastrous, and that the only way they would be together is if everyone was derailed and way out of character.