I just wanted to chime in with my strategy.
I fought him solo as a smuggler.
I tried staying near stairs like most suggested but that didnt really work for me. Heres what I did.
Covered at start point , fired one shot to get her to come in. Then I stayed there and fought until she used overload ( the big aoe) . the healing circles will start there and hit you before you die. when she starts overload i ran up the stairs out of the way, after it went off i looked on the side of stairs for the healing circle and then went back to where i started, and repeat that
hope this helps. good luck!