After spending a while looking for this connection, I finally figured it out. I figured it might be of some help to others to know where this door is. Video starts and ends at the opening where there is one door that you can open from the side door before you enter the layer, and one that opens from inside the treasure room. Hope it helps!
![](https://i.ytimg.com/vi/DzzCEljd4u4/maxresdefault.jpg)