Restricted Office // Lecture Hall

The Room frame lets one card hold two unrelated effects behind separate doors, and this UW pairing loads a control shell's late game into a single slot: a board reset on one side, a lockdown on the other. Unlocking the white door destroys every creature with power 3 or greater, which is symmetrical, so it will sweep your own beefy threats along with theirs; the power-3 line is the tax that spares tokens, mana dorks, and small utility bodies on both sides of the table, keeping the effect a scalpel aimed at midrange fatties and top-end bombs rather than a full reset. The blue door does the opposite work, blanketing your other permanents in hexproof so the planeswalkers, enchantments, and lands you have committed stop being answerable. The pivot is that you never choose between them. You cast one half at its own cost, then pay the other door's cost later to unlock it from the battlefield, staging the two effects across separate turns as the board demands: sweep when they overcommit, batten down your permanents once you are ahead. Both doors unlock at sorcery speed, and unlocking a door from the battlefield is a special action that never touches the stack, so none of this is reactive. The white door's destruction fires on the unlock; the blue door's hexproof is a static ability that simply switches on. Two answers, one card, sequenced on your own schedule.