Creatures in vaults will not be able to act (nor be damaged) until the vault is opened

game/engines/default/engine/Level.lua

game/engines/default/engine/interface/ActorTalents.lua

game/engines/default/engine/resolvers.lua

game/modules/tome/class/Actor.lua

game/modules/tome/class/GameState.lua

game/modules/tome/class/Grid.lua

game/modules/tome/class/Player.lua

game/modules/tome/class/interface/ActorInscriptions.lua

game/modules/tome/data/maps/vaults/amon-sul-crypt.lua

game/modules/tome/data/maps/vaults/bandit-fortress.lua

game/modules/tome/data/maps/vaults/circle.lua

game/modules/tome/data/maps/vaults/diggers.lua

game/modules/tome/data/maps/vaults/dragon_lair.lua

game/modules/tome/data/maps/vaults/forest-snake-pit.lua

game/modules/tome/data/maps/vaults/greater-checkerboard.lua

game/modules/tome/data/maps/vaults/honey_glade.lua

game/modules/tome/data/maps/vaults/horror-chamber.lua

game/modules/tome/data/maps/vaults/lava_island.lua

game/modules/tome/data/maps/vaults/loot-vault.lua

game/modules/tome/data/maps/vaults/mage-hideout.lua