Steele will automatically select whichever of Lane, Sera, Xanthe and Gene they're submissive to, in order of highest to lowest priority. Ara Kei will actually refuse to accept Lane, force Steele into detox mode (including breaking their otherwise permanent hypnosis), and consider the order fulfilled once the detox is complete. If none of the above are available, a Treated Steele with a vagina can also pass this order without getting a master. None of these options result in a Bad End.
Though since you've reached this point, it'll be impossible to complete Ara Kei's diplomacy mission without getting a Bad End unless you've already refused to join Fei An's harem.