07-06-2011, 04:20 PM
I can't look at this at the moment, but I"m guessing that's because the gray door is too far away from where Jack is when he activates the switch. Some sound effects are based on distance from the player, so the volume is softer the farther the object being affected is from Jack. This could potentially result in gray doors not being audible at all as they open if they are too far from him.