You are given a choice of methods of routing backbone cabling vertically through a building. The one option that you do NOT want to use is:

Open shafts (dedicated telecommunications chases or conduit shafts) are an approved and commonly used vertical pathway for backbone cabling.

Metallic raceways such as conduit are a standard approved method that protects backbone cabling during vertical runs.

Slots (floor openings or core-drilled penetrations) are an approved method for passing backbone cabling between floors.

Sleeves (conduit pipes cast into or through floor slabs) are a widely used and code-compliant method for vertical backbone cabling penetrations.

Elevator shafts contain continuously moving cars, counterweights, and mechanical cables that can abrade, pinch, or sever communications cabling. NEC Article 800.133 and ANSI/TIA-568 standards prohibit routing telecommunications cabling through elevator shafts to prevent damage, service outages, and personnel safety hazards.