No, I am not talking about the Hellfire Soaker- there is a flashlight to be found in the same building.
Going from where you got the hellfire soaker go to the elevator and down one floor. Enter the office in front of you- this is where the monitors i mentioned are located. After the conversation with Faith via these monitors turn around and go to the desk in the room- you'll find the flashlight there. Up on the top floor there is a dark room- go in there and use the flashlight to find the vault combination you will need to free Faith, located on the bottom floor of this building.