"Doom Boardgame question" Topic

I recently bought this game and my granddaughter and two of her friends really enjoy killing the monsters. But a question comes up.

The Marines clean out an area. No monsters left. They then go thru another door into another area and close that door behind them. Can I, as the Invader, then spawn monsters in the area the Marines already cleaned out? I'm inclined to treat the cleaned out area with a closed door the same as an area the Marines haven't been to yet, where the Invader can't move until the Marines have entered it. The kids aren't slouches when it comes to tactics, but I mopped them up in the starting scenario by spawning out of sight in the cleaned out area and just flooding them with Invaders. Seems like it is too easy for the Invader to spawn stuff behind the Marines. What is your opinion or rule or rule interpretation?

Not having the game I suggest the following as being in the "spirit" of the game:

If the Marines have cleared an area and leave you can only respawn there if it is connected to an area that the Marines have not cleared.

How's that?

The rules state (pg. 7, under Step 2: Spawn) that monsters must spawn in an area out of line of sight from a marine. Also, for purposes of spawning, monsters block line of sight to marines.

See also: PDF link

Oh, meant to say that there is no restriction on monsters spawning in "cleared" areas. Keeps the action going that way.