When it comes to building, I’m not the best builder in the world. I was going to try and create horror lighting, just to play around. And I’ll be honest…it looks horrible.
(This is if you want to increase visibility.)
You can increase the fog end by some, as well as making the ambient to a dark grey color instead of black. Hopefully this helped! 
Although this wasn’t exactly what I’m going for, you gave me some very helpful tips for something else I was going to work on! Thank you so much!
I recommend for horror lighting decrease the fog, also adjusting the appearance of the fog to more of a dark grey tint
I would recommend making it a bit more darker along with effects such as dust, smoke, or any small particles.
There’s many features when it comes to creating horror lighting, take a look at horror game lighting you would see they set a proper atmosphere featuring fog/mist - dark ambient - proper setting. The lighting can change depending on how your wanting the style to be.
Have you considered to tweak the atmosphere effect and lighting settings? Horror games feature a variety of ideas when it comes to accomplishing a good setting. It’s mainly just experiment instill you find a proper source tweaking the properties can result you into finding a setting that suits your liking;
I would play around with the properties it really depends on how your wanting the realism to go. You could include a PointLight in the middle and see what approach your wanting to accomplish with your little project.
Try changing the ambient to a black color and change the fog to a dark one and add blur and bloom
