I used to do it all the time, use the light beyond nemesis helm, select undying mind strike. When you get to the stairs part where all the yellow bars spawn you have 10+ chances of getting it, its very easy getting 7 orb supers with any character here. If you somehow miss your chance then simply move on to the boss, multiple yellow bars will spawn in 2 or 3 different locations, very easy to get here also. Ive never seen anyone fail that mission on that strike & i helped alot of ppl with it.