This is how I do it, usually run it as a 2-3 man. Enter arena run to the right. Stay in cover and locate the Eye. Once you see him shoot his head off. This will Agro him and he'll run the the stairs to your left and you can kill him easily. Make sure you time it so that the Jail Breaker buff doesn't run out before Qodron detains you. If you run out of Jail Breaker then separate your fireteam and destroy your own detainment fields. Keep fire on Qodron when you can, making sure you find Eye and take his head out to move him towards you. Rinse and repeat. I use this every time and it works like a charm. Watch for Hobgoblins that'll try and flank your left occasionally. Weapons like Icebreaker and Fatebringer are useful for taking out the Eye and damaging Qodron