Keeping in mind that this is a reproduction that was built no earlier than that late 1930's (and being wood, it seems logical to assume that it's been rebuilt more recently), this door scheme seems a little ridiculous...until you consider how much gravity would affect a door of that size and weight, were it hinged on just one side. How long would it take before that door started sagging in a dangerously insecure fashion? Plus this way your bastion defenders could have clearly delineated "in" and "out" sections of the portal, much as a busy restaurant might have separate in & out doors to the kitchen. Or maybe it was white men on one side, Indians on the other? The potential permutations are plentiful.

And we should certainly consider that vast gap at the bottom of the door, through which any of the ratlike little men who were the norm in the early 19th century could easily slither. But again, this is a reproduction, and surely the original doors sealed hermetically shut on carefully lubricated o-rings.