While killing bound in the Fawkes Clothing Factory I came across the room where Entry #1 is located, but I was too busy killing bound to get it. After all the hearst and bound were dead the door to thew room with Entry #1 was closed and I cannot enter. If there is some obscure way of opening the door after completeing the Factory you need to make it less obscure.
i currently have this bug. the room remains locked even though the infestation is marked as "completed" on the map. i am unable to access the essence reward and the lever to activate the factory.