Audio problem: When Sonny enters the old auditorium which will becomes Xanadu, he calls out to Kira, and she replies "Me?" however the audio is heard before we see her say the word. (00:18:05)
Audio problem: When Sonny arrives at work, as the Security Guards open the gates for him, we hear them chatting, but their mouths aren't open/are out of sync.
Audio problem: The tap dancing sounds during "Whenever You're Away From Me" are out of sync with their visual tapping.
Audio problem: In "Dancin'" when we see the keyboard player playing, the audio doesn't match to what he plays.
Audio problem: The rock drummer is out of sync with the drum sounds during the rock and roll big band scene.
Chosen answer: It's implied that it could be her, but there's no definitive answer as to whether or not it is. It's deliberately left to the audience's interpretation.
raywest