Even if the dungeon inhabitants are from a society where violence is commonplace, there are still the issues that (a) violence is likely a spectator sport thus drawing others to watch, and (b) the cries coming from an unscheduled brawl with another inhabitant or group of inhabitants of the dungeon are likely very different than the cries of combatants facing off against outside intruders. For example, non-combatants watching a fight between inhabitants might cheer on one or more of the combatants, but when confronted with intruders would be screaming and running for help. If the noise from the combat is high enough to be an uninterpretable cacophony, I doubt any occupants are going to be blase about the scuffle and ignore it completely.Youre assuming your average dungeon isn't full of sounds and combat on a relatively regular basis.
I can't think Orcs would think too much of rhe sounds of violence down a hallway even if we assume they hear it.
But yes, I am indeed assuming that the average dungeon isn't full of the sound of combat on a regular basis. Occupied dungeons are someone's home, and most societies frown on violence in living spaces. It's certainly possible to design a game world where "take it outside" isn't the common expectation, but I think that would qualify as an unusual game world.