The guards at the entrance of the Raider's arena did not even notice as Zane and Gwen covertly passed by them. It wasn't even a slow and stealthy movement. They quite literally just ran by. But their stealth rating was so high because of their advanced gear that they were quite literally invisible to the naked eye.
Inside the Arena's walls were dark, electricity had long since faded away from the world. And those who could discharge electricity from their hands were few and far in between. You would either need to come up with some new way to create power, or be immensely lucky to have such an awakened individual in your settlement.
For Zane and Gwen darkness was not an enemy, no it was a friend to them. They were Horde Kings through and through. Which mean they did not just have natural night vision, but also thermal overlays. They could very clearly make out everything that was happening in the darkness.