I just finished playing this game where my opponent cast the black room card Unholy Annex/Ritual Chamber. They cast the Ritual chamber side first and I killed the token during the same turn with 2 copies of scorching dragonfire. They later unlocked the Unholy Annex side and had no creatures in play for several turns after that. During each of those turns they drew a card and gained 2 life instead of losing 2 life.