Not sure if this is commonly known or has been posted before. Apologies if this is the case.
I just did the quest Tear of the Moons on my level 26 Rogue and found a way to have the mobs evade.
At the bottom of the fortress usually you will find 4 standard mobs plus a level 30 mob guarding the chest. The mobs seem to be linked so you get at least 3 mobs.
If you run straight to the back of the room and jump up onto the crates at the right hand side you can then jump up to the fireplace and the melee mobs will evade leaving you to loot the chest.
Sometimes you will get ranged mobs below the stairs so may need to burn them down, die and respawn before this will work. A nice exp boost at level 26 for a few minutes work anyway.
Be gentle this is my first post :wave: