Last night I was doing some level 22 missions in the Sanadian Wilderness and around one mission I found a glowing door, this was not part of the mission. For the hell of it since it was there I dicided to check it out. I went in mostly empty of inventory and came out mostly full (even my bags which are 12 slots) of level 23 items very easily. What I found inside was around ten or so level ones per room and weapon crates in each to open. Now let me remind you at there are level 23's all around the door and the area but if you can get in you can fill up on items. The location is "-3359 15 1625" for anyone that is interested in checking it out.
Funny, that door just teleports me back to the Helicopter Pad at Steelhead.
Odd, I've been through that door three times. Once for a mission and twice for loot.
I have since tried it again, and found I get two "Open Door" options.
The first one takes me where you're describing, but I get very few drops.
The second teleports me back to the helicopter pad at Steelhead.