"You guys have the right idea," Torrent says. "Let's go see if we can find Badgerface, or at least all the guards that are supposed to be here."
Down on the fourth floor you find several tower guards and one gnome unconscious and tied up. Nearby is a dead half-orc guard (the only one in the group) who's cause of death is probably the horrible burns on his face.
Torrent recognizes the gnome as Rivereye Badgerface, your contact. She quickly revives him and explains what happened to the party. Badgerface says, "That impostor must have been one of the elves who jumped me. They took the case I was carrying, but I convinced them it was trapped and I didn't know the password. There's no trap, but the case is locked pretty well. The Lyceum will be able to open it, but don't be upset if you can't."
"Go back to the people who captured you," Torrent says. "If they have the case, we need to find them."
"Right, right," Badgerface says. "Well, I overheard the elves talking to with that ball of light. I don't speak elven, but the light ball spoke celestial, which I do speak. It sounded like they had a contact at Gabal's magic school. The case itself is black metal, about a foot long and wide and half a foot deep. The whole thing is adamantine, including the lock."
"Okay," Torrent says. "Unless you guys can think of anything else we should do, I'll go get the guards from outside."