Kloudy
The Lore Savant
Well Arkus had entered when it was relatively quiet and underpopulated. It was only after a few had wandered in, setting off the previous inhabitants traps that the explosion attracted more. I'd wager there to be a few hundred at least, but they'll probably be more through the building. A few chasers would probably reside somewhere within the crowd, but that'll cause more problems for Pete than you when he starts attracting them. Best hope he can get up somewhere high or something.