Complete your group arena quests solo
When you ring the gong the boss needs to come from the right or left door, if he comes from this middle this is too hard to do to be usefull so if he comes out that door, reset it. When the boss comes out aggro him and draw him all the way into the far corner of the middle door (the one you face as you walk into the arena). The door will be closed but you can walk straight through it. Let the boss kill you there and res right away. Run back into the arena (the gate opens when you die) and tag the boss (who is moving to reset very slowly) and draw him out of the gate towards the enterance of the instance. Usually you will loose aggro on the way and the boss will walk very slowly back to reset. while hes walking away you can lay on the dps and he wont fight back. After he gets a little way into the arena he'll aggro again (off one of your shots in his back) and simplty repeate running back and laying on the dps when you reach the enterance. Sometimes the boss will walk back at different times but I'll leave you to discover the details, the spefics you should pick up quickly enough. If you die you can res around the time the boss is passing you and continue to kill him. Some bosses have a harder ai and you may end up dying repetedly, take healthpots so you can boost your health quickly as you will immediatly be retagging the boss and continuing the fight. You can do kill the bosses by dying over and over (doing damage each time) or you can do it by taking almost no damage as you get better at resetting their path and shooting them in the back. Either way its very forgiving in the fact that no matter what you do you can easily kill the bosses. This is verrrrry easy and you'll get a level 50 epic at the end, not to mention exp. and lewt. Hope you like this one because I have some better bugz to post later on.
*This is tested on only the last 3 bosses. Of them the ai on the last and 3rd to last was the easy kind and the 2nd to last boss was a harder version that required dying several times to take down.