Ok the reversed music chord and the smoke freezing right before Dianne speaks was the creepiest, scariest moment so far in this for me. The fact that Lynch left it unresolved is more genius. 

Lots in this episode, but those curtains and chairs and the conversation seems to parallel the red room scenes to some extent.

I agree. Definite Red Room vibes. 

definitely....also the fact that she says let's rock...Lynch is telling us something...with this scene and with the lady in red ...they are all parts of a bigger code

I near fell off my chair when i saw Diane swish through those red velvet curtains! And the intensity in her face before exclaiming "let's rock!"... so many clues, all hidden in plain sight.

I wonder if she's being manipulated or maybe held to ransom ~ could Jeffries be promising her good Coop in return for information?

I'm not at all convinced she's in cahoots with MrC. Not at all. It's too obvious + i also trust good Coops judgement in people he works with; he clearly trusted Diane.

The room was just too neat an emulation of the Black Lodge. Was it specifically set up that way, I don't know, in a ceremonial sense? It can't be by accident. I can see maybe Cole booked a suite for himself which maybe just happened to have a curtain for separation- and coincidentally enough, the curtain is red. But that room had bookshelves in it filled to brim with old books. Is this some new trend hotels are doing now? I generally do not stay in hotels of this type so maybe it is realistic and I just don't recognize it. Still, if the books are a recent hotel trend, then this must be the swankiest damn hotel in South Dakota. From the outside it doesn't look it- it looks like a 1960s era YMCA.

Okay, having watched it again, was that a side area of the bar separated by a curtain? If so, pretty loose talk about the Blue Rose stuff which was once so protected, Cole had that girl perform code just to communicate!