OK so i'm well past chapter 2 right now but when at a friends place as he was playing his IWD2 he became stuck on level 2 of the Aurulite Temple. The problem was with the treasure room next to the room with the mirror of entrapment. No matter how much we tried we couldn't get it open.
Now I can't remember exactly how I did it in my own game but was pretty sure the key lay in pointing the lightning cannon south and shooting ( all i know is it was open by the time I got to it) Well we tried that and nothing.
Is this the correct way to open this room or am I missing something?

If I remember right you have to go into the coffin room and find the one on the west side which has a "door". The door doesnt really open but after you try then shoot the lightning gun south.

Yup thats it I think. Because I remember opening the coffin in my own game before entering the treasurey and thinking nothing of it and never making any connection at all!
Thanks for the help mate :D