Potema's Refuge

When you first enter the door to Potema's Refuge, proceed down the corridor, when you come to the end there will be a dragur to your left, kill him and proceed. Walk down the winding hallway and up the stair when you reach the top, there will be a vampire waiting for you, kill her. You will then see a series of three levers, and beyond that three revolving doors (obviously the levers control the doors). Align them all to their open position (this will take patience as they spin pretty slowly, and can be a pain in the butt, but they don't need to be perfect, just enough space for your character to proceed through). After that, you'll walk through the doors into the next room. Directly infront of you, you'll be able to see through another window to a room with a chest and other lootable items in it, you'll be able to get to this later. You'll want to be very careful in this room as fireballs will begin shooting out of the walls once you pass the pillar in the middle of the room. I recommend using the Windsprint Shout to effectively navigate the room without being burned to a crisp. Upon windsprinting to the other side of the room, you will see that the cause of they mayhem is due to two lesser soul gems on top of two pillars. [Carefully] remove the two soul gems and you can navigate the room without fear. After that move through the next two hallways and proceed through the door at the end. Be ready for combat because there is a vampire fledgling(easy to kill) and a dragur deathlord(very, very difficult to kill) on the other side. Kill them both and loot them. The vampire fledgling holds the key to Potema's Sanctum. Loot him for the key and you'll be able to proceed through the door to the Sanctum.