THE CHAINED DOOR IS RASPUTIN'S
So it's safe to assume that the chained door at the center is Rasputin's since Tesla's is the vault and Nostra's is the one with the tree of life from the kabbalah (jewish tradition) as seen in the book of Nostra in the latest chapter (98). I'm now more intrigued by what's with Rasputin's character for him to have a chained door. What do you think of this?