I'm at the Fire Temple, wearing the snappy red robes, and when I talk to the Commander in the main hall he tells me Allrem can be found by going through the doors behind him. There is a large blank area on my map suggestive of a room, but I can't see any doors and when I move the cursor around I don't get the hand telltale to indicate where it might be. I've gone all the way around the temple in the main hallway, searching for a door on every section, and haven't found anything. What am I missing?
The door is actually at the other end of the hall, in the upper corner. There will be a couple of bugbears and another door across the hallway. Through that other door are the fire temple priests.
Assuming that you are at the correct place, Allrem should be behind the door towards the north-west area of his treasure chest.
Sorry, didn't mean to be so vague earlier: I've already found Allrem, I was just wondering if there was a secret room behind the altar in the main Fire Temple. There's a fairly sizable blank area between the main hall and the exterior corridor and I wanted to know if I should bother trying to find a hidden door.
