As we descend each level of basements in the secretive Corona Tower human-hybrid research facility, the total floor space shrinks, often due to underground untilities that couldn't be easily rerouted, and at other times to allow for what is located on the floor just above. Level 3 contains the natatorium with its deep-water pool, meaning Level 4 is notched out to provide room for the pool. The same is true for each of the basements, levels 2-5.

Basement Level 4 contains the facility's hospital, a cafeteria, and storage areas equaling several city blocks. Medical personel can access the underground parking garage on Level 1 with direct access through the hospital's dedicated elevators located just north of the cafeteria. Access is by passkey only, and only for hospital staff.

Access for pool maintence on the floor above and the storage tanks that extend through the bottom four levels of the basement complex are also part of Level 4's duties. 

During quiet hours, the rumbling of the power plant on the level below creates a low-key background hum in the hospital rooms, and the right-of-way for the city's underground utilities sometimes gurgles and spits with watery noises.

A distinctive feature that makes the hospital level stand out is the blue striping on the edges of the floors, giving the corridors the look of ribbon candy. The air is clean, with no odor of its own, providing a distinctive aroma unique even in the research center. The reason? The air is scrubbed, purified, and kept separate from the air pumping in and out of the other basement levels. No diseases in. No diseases out. What every good hospital should strive for.

Garik Shayk awakes in the hospital on Basement Level 4 at the end of Book 1 in The Human-Hybrid Project, Shattered by Glass.