I have found this challenge to be difficult at both the appropriate level and during gameplay. As you enter from the Veins of Helios, you immediately walk by 2 power cores and the object of this challenge is not to "trigger" them. That means that you cannot cause them to pop up in preparation of being charged to explode. They can't come out of the floor.
Here's what I do: First of all, I load an overleveled character who needs to complete the challenge, then I choose the easiest playthrough(normal mode) and if I am not already there I fast travel there. Secondly I make my way down to the stairs that lead to the area where you have to kill the first lost legion courrier. As you approach the bottom of the steps you will see a power core directly in front of you. Stay close to the right side of the bottom of the stairs and immediately and slowly work your way to the right, hugging the wall. From here you can move down to the level below and strafe back to the left minding that you stay about mid way in between any two power cores so as not to trigger them. You will notice the angled columns going up to a level above the level at the bottom of the stairs, you can climb the column up to this level. It's only a slanted ledge but it will give you a good vantage point. I snipe enemies below and after a a few minutes a power suit will spawn on the highest level just in front of you. I snipe him because he will immediately jump the opposite direction from you and you will have to move to another area. You can then work your way around the power cores from the slanted ledge and the level below, just watch where you walk. If you pay attention you can spawn the power suit noob who counts as a power suit and snipe him.
You can actually work your was around the upper levels and snipe more enemies until you spawn more power suits. There is one area where 2 actually spawn. The whole trick is to completely avoid the power cores. It just takes a little patience and you need to pay attention to what is around you.
Good Luck
If you need more help with challenges, my email martianpartyyahoo.com and my Playstation handle is Marty11406
1st edit, after fast traveling there, I caused a few cores to pop up but pursued completing the challenge anyway. I did complete it, but I have noticed this challenge is bugged, after reloading a character who had completed it, the area challenge list showed I had completed Finish Him instead, which I had not...
Sooo, it may well be that once you complete it, as soon as you save and quit or shut off your console the challenge won't show as having been completed.
