Question: At the Vermont lodge Judy is dancing with the same male dancer that Betty dances with at the same time in New York City at a nightclub. How can that happen?
Answer: George Chakiris is in the background as a dancer in Vermont, but then mysteriously shows up in New York.
He's a stalker.
Answer: The actors appear similar but they are different people. John Brascia danced with Vera Ellen in Vermont. George Chakiris danced with Rosemary Clooney in New York.