(You may cast either half. That door unlocks on the battlefield. As a sorcery, you may pay the mana cost of a locked door to unlock it.) When you unlock this door, this Room deals 4 damage to target creature an opponent controls.

(You may cast either half. That door unlocks on the battlefield. As a sorcery, you may pay the mana cost of a locked door to unlock it.) At the beginning of your end step, this Room deals 1 damage to each opponent.