Look at the map of Sector 8, there is an elevator there.
If your able to get to the safe room on that level (Stuff Room LTW-S8) in the corridor another door in that area is Cargo Archive LTW-8 just go through that door and go straight. That leads you to be big cargo elevator on your right hand side.
Only place that I can think of that matches what you described is pretty far off. If there is multiple spreaders and an infected girl in that room then that jump on the broken catwalk can be made for one of the hidden art cards. If that is not the area your referring to then yea no clue where your at.