This hall isn't nearly as large as the first space they had explored, but it is still fairly massive - it would take them about a minute to walk to the walls opposite from where they entered.
The walls are covered with windows, letting sheets of shifting prismatic light fall in to colour the pale stone of the floor. Pillars dot the room at regular intervals, covered with more of the spiral and wave designs, as well as more runescript. The ceiling is high, and arched, and appears painted to resemble the sky at sunset, a gradient of black-indigo-violet turning to rose-orange at the other end of the room. All four moons are visible in diffent parts of the 'sky', and the sun rests on the 'horizon' across from them.
Beneath the sun is a set of doors, made of the same pale stone as the rest of the room. Etched into them is a depiction of a shining Spear, which glows with pale blue-and-orange mana.