If you want to name the scene your song choice would show up, it's up to you. Obviously doesn't have to be prog.

Ideas:

-King Crimson's In the Court of the Crimson King is sort of a given.

-Voivod during Father Callahan's recounting of his days spent travelling the multiple worlds? Le Pont Noir seems especially relevant. They say the bridge is not what it is

-An improv session from The Mothers of Invention could probably work somewhere too.

-Have Adam Jones of Tool do a solo along the lines of Eon Blue Apocalypse

And even if you've never read the books, just think contrast and dark ambient and you should be pretty safe with what you choose.

Univers Zero