Episode 2

Passenger Experience Managers battle a language barrier to get 72 Chinese tourists to their connecting flights to Lisbon, but a problem arises when the group gets split in two and there's only one translator. Elsewhere, two of the Metropolitan Police's dedicated sniffer dog unit, Buster and Paddy, who search for explosives in the airport, are put to the test on a training exercise. Finally Water Services Engineers pull the short straw and have to clean a sewage tank - at midnight. But hunting for a sewage leak in the 500-mile labyrinth of pipes under Heathrow is no easy task.