//There's a concentration of activity up ahead, but nothing behind us yet. I'll keep watching.//

The walls around them are sheer, with no visible perch for defenders. Apparently no hidden ones either, since they're left unmolested until they reach the corner.

Peeking around it will reveal another large room at the end of the passage, open to the sky. Anything more is obscured by the massive pulse of void fire flying directly at them.