From the position of the damage it doesn't appear that the device was either at floor level or in an overhead locker, rather at torso level of a seated passenger. This could imply various things, from an deliberately fired explosive hidden on the person of a pax to a grenade accidentally detonated in someone's pocket - and Mog is a place where grenades are routinely carried. None of these obviously lend themselves to being a timed device. The choice of position, right over the wing, the strongest point of any aircraft, also does not indicate a bomber with much clue of optimising his efforts. If you had the gumption to make an explosive belt wouldn't you also know enough to set it off somewhere more vulnerable, or instruct your drone to do so?