Cant remember my level at the moment, but I do recall how I did this... it wasnt very professional, but heck, I did the job after all.
My char is a fighter/paladin, and always carry the sorcerer henchman with me.
I went in, killed one of the swords (had to use the henchman as a frontliner, so he died) and then quickly left the room. Rested, went in again, and to my surprise the remaining three blades where still wounded, so took another one out and repeated the process until the four were slain. Looted the chests, and stoneofrecalled my henchman back.
It did involve some reloading, though, but not enough to reach the "frustrated" level