Yeah Dark Al can walk and shoot through closed doors, and its always been like that
From when Dark Al was first implemented to FpsC X9 through all these updates, and they still can do it
In the past I've been trying to do some level design magic to hide it - like auto doors, or making sure that there are just no closed doors beetwen player and enemy in combat.... ;p but now Im just using good old chase, strafe, cover and snipe scripts (adjusted and edited of course). They not that bad, and far less taxing for engine. Now Im using dark al only when there is a need to arrange fight between allies and bad guys to show that player is not alone on his adventure
Aside from that, when you place in a room one enemy with - for example - cover script, and another with strafe, there is more variety in your gameplay, cuz not every enemy is behaving the same
Think about it