Not, it's not a memory vault since, as I posted above, the screen has animated "TV snow" in it and memory vaults don't have animated textures on them.
If it's a crack in the game polygons (a TV-shaped crack at that) then it is possible that the animated texture I am seeing could be the tornado (as kaecla posted) from the very beginning of Raz's mental journey. A tornado appeared next to Raz's caravan back at the beginning of his level.
Too bad there isn't a clipping cheat like most other games so we could wander through to see if the tornado is on the other side of the cavern wall.
(I could never get the cheats to work anyways...)