I think this discussion is worth revisiting, lots more people seem to be taking an interest in warbows. One thing i didn't notice being considered was the climate in thst region . Constant dampness and rain would cause serious rot, plus life then was filty. Who knows what parasites might have been living under a tarred oak surface. In addition to this, wood may have been weather proofed but if its a gate door then chances are its been through some horror before which may have weakened it.
It could be that that particular door was really rotten at a place where two pieces of wood were joined.. However in this day and age i doubt that any bodkin on an arrow of any mass off a bow of very high calibre could have leverage over the hundreds of tiny oak tree fibers such that it could pentrate it. Really wish someone could build a big heavy door to try it on, i dont think stacks of homedepot red oak will do it justice =P