The fate of the Empty Crown after the events of the Exomorph crisis are unknown; they may have been decimated or their organization may still exist within the Romulan Star Empire. However, Kleeya has revealed rumours to the attention of starfleet that a master key has been built, allowing control of exomorphs without the need for a control facility.
Round up that entrance on the bottom or make the outer edges to some sort of door frame with a different texture on it. Other than that good work.