[From here.]

The moment they exited out into the hall, it was clear what the source of the explosion was. Halfway back down the corridor, a bright, blazing light was coming from one of the rooms. A fire? Guy stiffened for only a second before he raced over, a sense of dread already settling in. If someone had gotten caught up in the blast, then there was basically no chance that they'd actually survived.

Forced to stop when he got within about five feet of the room, Guy winced back from the heat, putting his arms in front of his face as he tried to peer into the destroyed room. It was hard to tell, but he was fairly sure that he didn't see any bodies in there. Besides, chances were they would have smelled something, as grim as the thought was.

Guy looked over to his friend, doing his best to keep his calm so that Luke didn't overreact. "It doesn't look like it's spreading beyond the room itself," he said, trying to point out the silver lining. He wasn't sure why it wasn't spreading, but it wasn't like they had any way to stop it either way.

The real question was, what had caused this? Rooms didn't explode into flames all by themselves.