Was the last Guardian outside the portal, and 1 of the 3 guardians inside the portal went down.. AKA it was about to wipe.. But when I realized how low Atheon was.. I popped my Golden Gun, put all 3 rounds into that bastard and then pulled out my trusty Icebreaker and put round after round into his critspot.. And oh how satisfying it was when the mighty Atheon fell and I was rewarded for my badassery with a glorious Vex Mythoclast!