I am currently having problems with this mission, I've tried with henchies/heroes and other ppl. We still don't have enough time to kill the enemies surrounding the crystals. The enemies here tend to heal themselves plus there are multiple bosses around it. I've even tried soloing it just by running without killing using the following skills on my warrior:
Rush, Rage of the Ngouka, Heal Signet and Holy Veil
Usually I get blasted by arrows and spells, plus the mines cripple me. It was getting so frustrating that I went back to Night Falls and continue the missions there.
How did you guys do it? There isn't plenty of time to kill all enemies within 30 minutes. Any suggestions would be greatly appreciated.