Can you re-enable areas once used?

[Your Computer]

Okay, the best way i'm going to understand this is if i ignore the existence of the current areas.

So let me get this straight. If the player walks into the room, the door closes behind them. If he exits having picked up nothing, then nothing happens. If, however, he picks up the key, the door opens slightly if not already open (or possibly open even more than what it already is). Having the key in his inventory, if they attempt to walk out of the room, the door closes on them.

You only want this to repeat if the player hasn't obtained the key in the room.

Is this correct? If so, this all may require no more than 2 areas.