Create a folder called "Sound" in your ...\World of Warcraft\Data\ folder.
Create another folder called "Creature" inside of "Sound".
Create a folder called "XT002Deconstructor" inside of "Sound".
Inside of "XT002Deconstructor", create a new, blank file of any type. Name it "UR_XT002_Adds01" and change the extention to .wav.
Copy and paste and rename it for the following:
UR_XT002_Aggro01.wav
UR_XT002_Berserk01.wav
UR_XT002_Death01.wav
UR_XT002_HeartClose01.wav
UR_XT002_HeartOpen01.wav
UR_XT002_Slay01.wav
UR_XT002_Slay02.wav
UR_XT002_Special01.wav
Problem solved. Only draw-back? You can't hear the real boss.
This does NOT affect your .MPQ or other related data files, and there was a blue post somewhere saying that they allow sound changes done in such a manner. In order to undo this sound change, all you have to do is delete this blank file.
Attached File With Folders and Files All Set Sound.zip