This might have been covered but I thought I would mention it. So first off as had been discussed the lack of a timer at the end of the VOG is a possible sign there is a chest to find after the raid. The door at the back of the vault opens, we have probably all seen that and I imagine it's been well explored. It is a possible location after a perfect raid but I think it's quite obvious and possibly doesn't need that long to reach. Today we were farming some glimmer at the gate keepers stage and I decided to explore. On the left side of the map as you enter there is quite a lot of ledges and so on, none of these have any invisible walls to stop you reaching them. From the tower on the left gate I was able to get across to the ledge that's about level with the top of the gate. I was actually using a double jump and blade dance to get across but looking at the tower and surrounding area I think it may be possible to get across without that ability. Once across I headed toward the back of the map up a through ledges then back towards the front of the map over a rock and back on to ledges, you can jump across in the direction of the vault entrance but now on the outside of the left wall. Drop down from here and there is a little room, no reason for it to be there, you can't see it from the main part of the map at all but it is there. And I think it might be there for a reason. Next time we do the VOG I will check it out again although I imagine it might require a perfect raid on hard and I am nowhere near good enough. If someone wants to check it out? I will try and get a video of the location together when I can.