I hear the banging

When you walk down stairs to the lobby area you will hit a trigger before you walking into a corridor full of doors. The trigger you hit will just make two doors open and close slightly. When you in this corridor. There is an ambient sound node playing a sound of banging doors that is seamlessly looped thanks to Jasdev. Jasdev created great fade in and fade out of the banging. 

Top of the stairs volume trigger box

Bottom of the stairs volume trigger box

Doors moving in and out slightly kismet

Bangin ambient sound node