Traveller Tales: Inside an airport security scanner

Question: what DOES it sound like on the inside of an airport security scanner? I wondered that too. The plot formulating inside my cacophonous head yielded a not-so noisy mechanism: I'd discreetly slide my iPhone onto the plastic tray, recording as the conveyor slithered into the machine and swallowed my belongings. There on, my phone and I embarked upon separate journeys - as I passed through the metal detector, cunningly dodging a groping, phone en espionage captured the sound of monstrous grumble.