I don't know if i'm the first person to notice this but i accidentally hid inside one of the Vex portals...run straigth at it and got stuck between the backplate and the holo thingy... and even though Skolas and a dozen ads were just in front of me they wouldn't fire at me. A few Icebreaker shots to the head and he was done. This was level 30 difficulty with a level 31 Hunter.