That is, by far, the most accurate SCP genre hallway I have witnessed. While most developers make SCP style hallways dimly lit and claustrophobic for atmospheric purposes, they usually miss the point. The space you put in the hallway really applies the authoritative tone the Foundation usually has (being the most powerful organisation in the world ofc).
In addition, the architecture works with the underground theme, with strong concrete supports etc.
Though there are some things I’ll like to add.
If you read a lot of SCPs, you will eventually come across a pattern. This pattern is usually defined by the contest the SCP Wiki provides for authors to input their own SCPs. For example, the Doomsday Content for the 3000s entries and the Mystery Contest for the 5000s. However, in a lot of SCPs now-a-days, groups of interest (GoIs) such as the Chaos Insurgency and the Church of the Broken God (or even all of the GoIs in SCP-5555) are a major part of the SCP entry for interest purposes.
Of course, the Foundation’s main missions are to secure contain protect, but with many things, it is not as simple as that.
So, I would definitely try to include more security measures such as automated turrets and cameras or even augmented humans. The Foundation gets raided a lot so these measured would be standard expectations for any Foundation facility. Not to mention the containment breaches.
Anyway, this was an amazing build in general. Keep up the great work.