Well spiral, all i will say is where as your laboratorys were filled with an external terror H.R. Giger style, this darkness will come from within.
You'll just have to wait and see.
My insipration is from a multitude of sources.
Your Laboratory levels, H.R. Giger and his creations, movies like the Descent which feed on our innner fears.
The darkest kind of fear is that which is in ourselves.
Insanity, fear, sheer horror, borne from inside us all.
hehehehehe . . . . .
Ambience similar to the Labs.
That dark, spooky, eerily emptiness possibly?
I haven't decided fully.
As my own fears come to light, then shall you meet the darkness.