Deliberate mistake: As Christine approaches the Phantom in his lair (just after he has abducted her), we see that she is wearing very dark black eye-shadow. Back in the dressing room after coming off stage, as she talks to Raoul, we saw her face in close up and she was not wearing any eye-shadow at all, even though the Phantom leads her through the mirror just after she has managed to slip on a robe over her undergarments and she has not yet changed to go out to supper (Raoul says she is to be ready in 2 minutes). Her hair becomes 'bigger' and wilder, too. The change in her appearance is a reference to her descending (voluntarily, I might add - he didn't drag her through that mirror) into the Phantom's dark existence and to her sexual awakening. (00:28:45 - 00:37:10)
Answer: During "Point of No Return, " the Phantom shares a stage with the very vulnerable Christine. He is still masked, though it is a mask other than his trademark white face covering. The Phantom is well known as a murderer and an escape artist. This is the the equivalent of a hostage situation. To rush the stage might risk lives, and everyone in the know is proceeding with caution. During the song, we do get glimpses of police moving about, and Raoul and others looking concerned, subtly signaling one another and considering their next move. The stage crew seems confused. The dancers go on with the show. And law enforcement officers await the right moment to advance. It also gives us the opportunity to enjoy a dramatic musical number that rushing the stage would interrupt.
Michael Albert