Tnxs 'HotDog' am just thinking of other causes that's all. Close examination of the flap in the pix tends to show to me that perhaps it was jammed for unknown reasons & by the looks of it the attatchment point for the jack is at the L/H end (or close to it) meaning the jack pushed that part out but the panel failed about mid point, just an observation. Previous damage in some form is a very real possability however I think.
CW