maybe not, the labyrinth was created to hold many more children of poseidon as prisoners, but athena got foiled on that. also the realm stays there even when asterion moves away in some of the ruthless endings. the question is if the hotel can be kept running if the realm doesn't have a master, or if there can be a master if there are no prisoners.
however, considering hermes request, it's quite possible you might destroy the realm inadvertly. but it could be just one of many endings there will be.