Actually you don't need to do any fighting at all for this quest.

What you're supposed to do is sit by the Padjal in the back (forgot his name) and let the npcs that assist you do all the dirty work. The npcs will eventually cycle in and out as they take damage, so no worries about being the only one left on the field.

Now you may have noticed at certain points of the fight, the elemental will change it's element. At this point, talk to the Padjal and select the element of the barrier that corresponds to what the element is now using. Then you should get a new command action, something with warding. You get 3 charges of this ward to place (usually on your npc companions). Rinse and repeat as the element keeps changing affinities.

Sometimes you may pick up a little aggro. Just as long as you never take any real battle actions (don't even cure of buff yourself of any sort!), place the ward up, and stay out of the aoe range of the elemental as best as you can, this should be a lot easier to bypass.