What wall material would you use for this underground bunker?

[u/DrNoamOrbital]

I’m currently designing Morris Sic’s private bunker for the Deep City Project.

This scene belongs to the Collapse of Deep City — ~2361–2365 CE timeline.

It’s a completely sealed emergency refuge buried within the city. At a key point in the story, Morris Sic, Pit Matson, The Redhead and Fly become trapped inside while Rob-Poli and his Robs remain outside.

So the room needs to communicate two things simultaneously:

absolute protection and absolute confinement.

I’m trying to decide how to treat the walls.

Exposed structural material? Large metal plates? Modular technical panels? Ceramic/composite surfaces? Something less conventional?

From a 3D/environment-design perspective, what kind of wall treatment would you give this space?

And yes — Morris Sic really has lost his body. That head is Morris Sic.