Resolve corporate_plaza north exit unlock behavior (WC2)

Decision WC2 flags ambiguity: corporate_plaza.north has requiredFlag tower_breached, which is set by Puzzle 2. But the engine uses both locked/unlockExit AND requiredFlag checks. Need to verify: does the engine dynamically check requiredFlag on every go attempt, or only unlock via puzzle unlockExit? If dynamic, both tower entrances open simultaneously (correct). If not, add a second unlockExit to Puzzle 2.