Sanctum is a speakeasy locates in the Grand cafe. When you enter there are stairs that take you up to the second floor. You'll be thrown off my the tables and chairs and people studying. Continue toward the only door on the second floor. Once you're inside you'll see that it's a small space. You'll immediately walk into the bar and see that the menu is also limited.
I got the Blue Wallis. For me it was too strong. I got the vibe that this was a no substitution, no nonsense kind of place so I just didn't finish it. My bf loved his drink though so there's that. If you're not a fan of strong drinks this might not be the place for you. I guess it's partly my fault for not asking but I was overwhelmed by the scene.
I will say that I doubt it is like this all the time but when we went there were a group of people who were dressed in cosplay. They all seemed to know each other and weren't particularly rowdy until Jesus showed up. Yup, you read that right. The bartender quickly called security and that was handled but I guess you never know what happens at a bar.
All in all, I think this is a really intimate space. If that's the tone you want to set then this is the place to go. Drinks are on the stronger side but I'm sure they do well drinks also. I'd suggest going at least once just for the experience.