Ouch, that's an unfortunate way to die. If you get the message for a tension room in DH, it is usually a good idea to flash a wand of monster detection (actually, it is a good idea to do that regardless, in case there's a greater demon or quickling queen on the level somewhere). You would have spotted those mimics with the wand, and could have safely avoided the tension room. Having a tension room on the level that you haven't activated actually makes DH generally very safe, since there will usually only be 1 or 2 other monsters on the level at any given time, so you pretty much have the run of the place.
Hoping to win with every class, doomed. Archer, Barbarian, Bard, Beastfighter, Druid, Elementalist, Farmer, Fighter, Monk, and ULE Priest down.