This one's trickier. The room is quite narrow, and it's not a simple matter of expanding the walls outwards. The wall on the left is the exterior wall of the show building, and the wall on the right borders on the bit of track between the skull room and the aforementioned dark passage. As much as I would love
to see fully-developed sculptures instead of murals on the walls, I don't think it's gonna happen. They'd be close enough to touch.
Instead, the walls could be redone to look like stone. They'd have sculpted faces and bodies and such incorporated into it, a la
the beginning of Raiders
. This'd be more realistic and less tacky-looking. I'd imagine the idea probably came up in the concept phase for the attraction, and if it were me, I'd have initially dismissed the idea because of the lack of visual impact--it might not "read" quickly enough. To take care of that, I'd suggest lines deeply engraved in the relief, with reddish-orange lights set back in them. These would begin to glow a moment after you entered the room, illuminating the patterns of the skeletons or whatever, suggesting the power of Mara entering the chamber, and the dart effect would begin.