Revealing mistake: During the big fight scene, you can tell easily that Frank is wearing knee pads (try looking when his pant leg is wet). Construction workers will often wear knee pads for work but most often they wear them on the outside of the pants to save the knees of their pants. (00:58:50)
Revealing mistake: After Holly tells Nada that she works at Cable 54, he springs to his feet, and she cracks a glass over his head which dramatically sends him crashing out her bay window, to the bank below. Which would not happen in such a pricey home as hers with the thicker quality glass.
Answer: Yes, she was one of them all along, she was playing dumb, even when she showed up at the underground meeting, a double agent.