there is a randomly generated "lost and found" quest (as in, when it appears for you or becomes available to do; is RNG.. so always watch for an icon @ the reef) from petra that also needs to be completed. so that, her normal quests (taken war), and the variks quest = boolean gemini. I actually got the lost and found quest early before I completed the last park of varik's quest. Once I completed it, the queen had the gun waiting for me.