Usually a concept is designed with story in mind but in Titanfall, it's designed with gameplay in mind.
Designing anything in Titanfall including interiors is a little tricky because walls need to be flat for wallrunning. To make a flat surface looks interesting is pretty challenging and that is something we face daily.
The wall needs to be flat for wallrunning here. There can be a little inset here and there, but it's very minimum.
The hallways needs to be wide and tall enough for titans to play, and it makes pilot wall hopping a little easier.
The tone design of the Militia (or MCOR) is usually warm and/or colorful with "used and dirty" feel. Where as the IMC are cold, clean, and sleek.