Yea, i'd suggest putting the mic in the middle of the room, and setting it to a figure of eight pattern, so that you don't get the 'proximity effect' when people move closer to the mic. That way you can use the ambience of the room, without close people seeming really boomy (unless it's Brian Blessed).
-- if you do use a figure of 8, by turning the mic 90 degrees, you should be able to get rid of a lot of the fan noise like with the cardioid.
If you leave the mic in the same place, and move the actors about, you get a better sense of one-ness, compared to moving the mic and the actor.