Bringer of Doom not spawning

[PenumbraPenguin]

I ran into the three pedestals that summon the bringer of doom, on the bottom level of the ogre complex. I activated one and killed the resulting monster. The second one I stepped on and examined, but I was completely surrounded by walls, except for the square containing the first pedestal, and one of my temporal hounds was standing there. (It's also possible that other hounds were occupying the only squares at distance two, I don't know). No enemy spawned, and the second pedestal was then unavailable to interact with again. I couldn't find the enemy upon searching the level or digging around, so I don't think it spawned.