Either Boy or Girl will decide they have to leave whatever location the whole movies events are occurring within, whether it be by plane, train, boat or automobile. ... But not space ship, as this could be construed as original and this genre tries to avoid such a trait. The "betrayal" they have "suffered" as a result of the aforementioned misinterpretation / miscommunication is so HUGE that they must give up their jobs, their homes and their friends and family in order to completely evacuate the city or the country and start again.