Night Lords Trilogy, p. 557-559:

The walls, like so much of the Legion’s fortress, were formed from black stone sculpted into forms of torment. Twist-backed humans arched and writhed motionlessly, captured at moments of supreme agony, their wide eyes and screaming mouths shaped by sadistic devotion.

Shaped. Not carved. Talos hesitated by the doors, his fingertips tracing over the open eyes of an infant girl reaching for the protective – worthless – embrace of an older man, perhaps her father. Who had she been, before the Legion raided her world? What had she done with her short life before she was dosed with paralytics and coated with rockrete? What dreams were quenched by her living entombment within the hardening walls of a primarch’s inner sanctum?

Or did she know, on some panicked, animalistic strata of her dying mind, that in death she would be part of something more momentous than anything she’d achieved in life?

Within the stone, she would be long dead. The mask staring out at the world immortalised her in the naive perfection of youth. No tracks of time across her face; no scars from battles against an empire that no longer deserved to stand.

He withdrew his hand from her frozen face. The interior doors opened, bathing him in the warmth of the inner chamber.

The Screaming Gallery was in fine voice tonight – an opera of bass moans, piercing cries and the ululating chime of sobbing beneath the other sounds of sorrow.

Talos walked down the central pathway, boots thumping on the black stone, while the floor either side of the walkway rippled and tensed with the pliancy of human expression. Eyes, noses, teeth, and tongues poking from open mouths... The ground itself was a carpet of faces flesh-crafted together, kept alive by grotesque, baroque blood filters and organ simulator engines beneath the floor. As an Apothecary, Talos knew the machinery well: he was one of the few charged to maintain the foul ambience within the Screaming Gallery. Robed servitors mono-tasked for the duty sprayed gentle bursts of water vapour into the blinking eyes blanketing the floor, keeping them moist.