You do not need to fight all 4 DKs at once. That happened to me once, but after I reloaded I approached slowly, and fought the first 2 together, then the other 2. Leave one character at the exit using a ranged attack, for a possible quick get away. Try to take out the archers first, then if necessary a melee character can run around as a distraction for the other DKs while a ranged character does all the damage.
BTW, the weapons officer that teaches identify is on the first level of the citadel, NE of the entrance, in the room that had all the good equipment you could not reach.
