Given the following context:  Pat, a hotel switchboard operator and Peter a crane operator are a happy well meaning couple, however because of their different shifts during the day they have no time for each other. While he works during the day on the construction of Waterloo Bridge his patient wife works during the night on a hotel telephone exchange. One morning on his way to work, Peter goes on the London Underground train and spots what seems to be a murder being committed on at the open window of a building overlooking the tracks. Deciding to investigate this "crime" Peter and a policeman arrive at the residence. There they find out that the couple were in fact rehearsing an illusion. Zoltini is a bad tempered magician and his wife Vivienne is his assistant. The suspicious magician becomes sure that his wife is having an affair with Peter - every time he sees her with the handsome stranger. On another night Zoltini and Vivienne have an argument on the backstage - leading to him slapping her in the face. As a result, Vivienne leaves (while her husband performs on stage) and takes a taxi with Peter up to his crane. Furious with Vivienne for leaving during the 'vanishing women' sequence of their performance, Zoltini looks for his wife while Pat has been sacked from the hotel for not paying attention to her job.  answer the following question:  What does the magician's assistant leave by while her husband's performing on stage?
A:
taxi