I remember on EFU that doors had a script that meant if something like 30 seconds passed everybody speaking within the confines of the door couldn't be heard by anyone outside anymore if they were using Talk.
It might just be me, but I've noticed this doesn't seem to be the case with any doors in EFU:A. If I'm not off the mark, could I suggest that most if not all doors receive the script?
You can hear through most doors, if I remember correctly, so why shouldn't you be able to in game?
It wasn't a script, just a nwn engine "feature." It has to do with how the area is built and the resulting walls that the engine (seemingly randomly) decides you can listen though either permanently, or 30 seconds. I have no idea how the black magic works.