Just in case the idea I'm going with isn't quite right I have a secondary, back-up idea just as a precaution. So far this idea is only in a mental stage but it is similar to my current one.
Instead of the set being an abandoned warehouse illuminated by an exterior light through a collapsed roof, I was think of patching the set up and making it look like a working factory at night. Replacing the majority of the larger objects would be industrial machines all of which would be inactive due to worker having left which still keeps the sense of abandonment. There would be a light emitting from one of the distant machines and the lights above it would be on but be quite dim.
I'll get a few drawings of what I have envisioned for this idea up asap just so it explains things a bit clearer and shows what I'm trying to get at.