There are a lot things to worry about when you step onto a plane. Will you get a window seat or be stuck in the middle seat between two complete strangers, both of whom laid early claim to the armrest? Will the plane take off on time or will an unexplained delay keep you parked on the tarmac, playing Candy Crush and praying to whichever aviation gods are in charge of air traffic control? Will they run out of coffee by the time the cart gets to your seat in the very last row? But one thing you rarely have to worry about after the cabin door has been closed is whether your plane will have to make an unscheduled landing mid-flight because a woman attacked her husband after she found out he was having an affair. That is, unless you happened to be on this recent Qatar Airways flight.