What's the purpose of the revolving door? On bast, it's a chokepoint, as it's one of two ways to get to engine hive and refinery hive without going through feedwater, and the only way to get to refinery without going through engine or feedwater.

Yeah, its an old layout, but you get the idea. On your overview, the door doesn't seem to server much of a purpose. It's a large, slow moving passage, and a critical chokepoint. If marines cannot pass through the door due to aliens controlling Main Aft, they HAVE to go through engine or double/feedwater to get anywhere. On your layout, they can simply go around. It would be a great feature for a map if it serves a good purpose gameplay-wise.

Here's one suggestion... the weld point is easily defendable by aliens, but if welded opens a really fast path to the hive (ala Daimos, like the pic says). The aliens can get around it with that vent, and the door is a nice big chokepoint.