Plot hole: In Jonathan's ballet at the workshop, Sergei proceeds very slowly through an array of twenty dancers before reaching the leading lady, whom he expects to be Maureen. But instead it is Eva, whom Maureen has asked to take her place. When Sergei sees Eva, he is extremely surprised. I guess that could make sense, if he's been focused on his own dancing. But the stage crew and several dancers in the wings start chattering confusedly, as if they've also just seen Eva for the first time in that same moment. However, Eva must have been standing there for several minutes, or at the very least had just walked through the crowd of surprised people, and Maureen must have been missing from her spot this whole time, so these people should be in mid-reaction.