This is what the door inside Bunker RAS-2 leads to, the Seraphim Vault. The only acessable areas so far are the entrance hallway, a semi circular hallway, and a viewing area with a big window that shows a room that I assume holds Rasputin. Its a little difficult to get to, but the video below is pretty good at showing you what to do.
Once you go through the trouble of glitching through the map, climbing and jumping around invisible walls, then landing on the railing, you'll end up here.
View of the entrance from inside the hallway leading into the vault.
At the other end of the semi circular hallway, you'll find this door. Now, I know I said the vault may have something to do with the Warmind Rasputin, but this door makes me think the vault may be owned by the Seven Seraphs, a supposed faction yet to be seen in Destiny. What makes me think this, is that there are seven markings on this and other doors inside the vault, and the name of the vault itself, Seraphim. Maybe I'm over thinking it, or maybe its something completely different. We'll have to wait and see.
Halfway through the semi circular hallway, you'll come to these stairs. Go up, and you'll come across...
This. Tons of wires, cables, and other things connected to whatever that is in the center. Rasputin? Something to do with the Seven Seraphs? Only time till tell.
Going back to the Forgotten Shores, past the rock you use to glitch through the map. Keep going until you find two Dregs. A little past them on the left you'll see a path. If you follow that you'll eventually come to a large storm drain, with a familiar looking door inside. Could this be the exit from the vault? Or could this lead to something else?