I see the rules about how you spawn monsters in a new room when you "reveal" it by unlocking the door. However, in some maps there are already open passageways between map tiles. Does that mean the monsters on these tiles are all already "revealed" and spawn immediately from the beginning of the scenario? Or do I still have to have a character walk on or look into the tile to activate and spawn the monsters?
I assumed the that they were revealed but noticed that in one of the scenarios I would run out of creature tiles for a specific type if they were all revealed at once in the large open multi-tile cave with no doors.