Bill dutifully informs the pilot and looks around at suspicious passengers.
Then with the help of a flight attendant Nancy (Michelle Dockery) and Julianne Moore, whose character has curiously managed to bag a seat right next to Marks in first class, draw up a list of suspects which includes; a rude bald man, an obvious Muslim doctor, a weirdo with glasses and a few more. Whoever the tormentor is, he knows something about Bill and definitely knows his way about.
Progressively, someone does expire, and another after that. It also turns out that the bank account is in Bill's name. As the plot thickens, the trick card played by screenplay writers John W. Richardson, Chris Roach and Ryan Engle point the finger of guilt directly at Bill, who is supposedly on board to protect the passengers from any such culprit.