The commute from Heathrow to London was an everyday occurrence for some onthe subway. For others, like Kristin, it was their first. Kristin had landed at Heathrow a few hours earlier and had steadily made her way to the underground. She had a hotel booked before her trip to Europe and she would be staying for just a single evening before her adventure began. At first, the train was relatively empty. A couple seats were ta...