As I was playing with the Howling Peaks DLC, I decided to go and try to get the so called "Woolly Wisdom" achievement. After researching online, I found out that the room was only to open if I didn't kill any llamas during the Gale Sanctum. So, after playing the mission over 20 times on the lowest possible difficulty to minimize the amount of mobs and maximize the chance of getting the room, I still could not open it, even making sure to equip gear with the least AOE damage, and didn't hit anything that I didn't have to.