I dont have a lot of time to really analyze the image well enough but here's my quick take on it.
I think a main point to consider here is that the hue changes in the example image are not realistic at all, and steel panels of that color in real life would look very silly. It's important to understand the difference between monochromatic ramps and multi hue ramps. Your rock example is not monochormatic. A monochromatic ramp will not take into consideration any sort of saturation or reflective surface of whatever object you're constructing. The difference between a dramatic hue shift ramp and your rock example is just basic realism. If you add greens, purples, and blues into your rock it all of a sudden implies different things about the surface of the rock and the lighting that strikes it, and this should be done in strictly stylistic choice to add an overall atmosphere, similar to how lens filters are used when shooting film. Because you're working with pixels it means that you can exchange multiple hues together and make the image look almost identical while using the appropriate brightness and saturation levels. The only reason the hues are so shifted in the first image is because of over dramatization and dramatic atmospheric elements.
For example, the highlights on the metal plates is green and red, shifting towards purple, implying a green sort of ambient light is being reflected off of the metal. You could probably imply that the metals are two colors, some are redish some are bluish, and the ambient blue light is reflecting off the blue surface creating sort of a dulled down green color, and I'm guessing the red from the other metals is reflecting in as well.
So here's a section
And here's a b/w version so you can tell exactly what colors the highlights and shadows are.
And here's a color edit with a more straight forward pallet where it's clear why the colors are changing based on the lighting.
So the main point is that the hue shifts being used originally are being used to give the room a more rustic and ambient sort of look. Complimentary colors will give the environment a more dramatic look and build more atmosphere. To learn to how achieve this you should stick with the basics red yellow hue shift (generic outside lighting and reflective surfaces) and then edit it to see how the entire picture will look with whatever look you want to give it.