What the fuck do you do when you return to the hub with the key? I can't find a lock for it, there's two chalk outlines of doors in the basement that both say "NOT THIS WAY" in front of them and there doesn't seem to be anything else I can interact with. The exit door with the boneworks box behind it is still closed, nothing happens when I press the button, the key doesn't come with me when I enter any other levels and it can't be stowed in my inventory. There must be something i've just missed in the hub area but I am totally stumped.