Doors can have a "door_sound" field to tell which file to play when opened

game/engines/default/engine/generator/map/Static.lua

game/modules/tome/class/Grid.lua

game/modules/tome/class/NicerTiles.lua

game/modules/tome/data/general/grids/icecave.lua

...tome/data/gfx/shockbolt/terrain/icecave/icecave_door1.png

...data/gfx/shockbolt/terrain/icecave/icecave_door1_open.png

...gfx/shockbolt/terrain/icecave/icecave_door1_open_vert.png

...ockbolt/terrain/icecave/icecave_door1_open_vert_north.png

...data/gfx/shockbolt/terrain/icecave/icecave_door1_vert.png

...fx/shockbolt/terrain/icecave/icecave_door1_vert_north.png

game/modules/tome/data/maps/wilderness/eyal.lua

...les/tome/data/sound/ambient/door_creaks/icedoor-break.ogg

game/modules/tome/data/zones/wilderness/zone.lua