FAQ Question Regarding Rooms

[Raineer]

In the base "Munchkin" forum, the "Critical read this first" post contains the following sentence:

Rooms: Any time someone kicks down a door and does not get a Room card, a Room may be played immediately from anyone's hand. Once a non-Room card is played on a combat, a Room may not be played.

The phrasing of this is confusing me. My family is new to Munchkin and we are playing Munchkin Deluxe.

To my knowledge, we kick down the door and draw a door card. I don't know what a room card is. This makes me think if I draw anything but a monster - then someone else can play a monster if fast enough (without needing a wandering monster card) - but I have no way to verify what cards are "room" cards and which aren't.

Or this may apply only to an expansion I'm not playing.

Thank you for such a great game.