Mary put her briefcase on the floor beside her as she looked out of the window of the train. Another passenger (Randall) put an identical briefcase on the rack above the seat across from where Mary and her daughters were sleeping. Then the man rushed off to the restroom. The train made a jerking motion as it took off and Randalls briefcase fell to the floor across where Mary was sitting. Marys briefcase moved further down. Mary heard the noise and...