What about the worms?

The hotel's ventilation system was a labyrinth, endless ducts, twisting and turning, connecting to every part of the hotel. No one could possibly navigate it without the use of a map and a few hours of studying. The worms had no such issue. They had no higher thought, only the base instinct to find uninfected human flesh and spread their father's scourge. The darkness of the vents was no obstacle to the eyeless creatures, their senses able to detect what was directly in front of them and their goal, making anything else irrelevant. They would reach their targets eventually.

Being creatures created from a primal form of the virus, the worms had a highly unstable physical structure, highly subject to mutations and the introduction of foreign material. Two of the slugs ended up pressed together, their flesh fusing together until they resembled something like a octopus with only four legs. It quickly used its newfound limbs to propel itself faster through the ducts, its base intelligence fixated on a distant target. Soon after, a small spider had the misfortune of crawling over another of the crawlers, its long legs sinking into the things body as it was assimilated. The worm naturally copied the small arachnid's body structure, growing spindly legs and a gaping, tooth-filled maw. It scuttled up a vertical shaft, seeking prey further up the hotel.

Elsewhere, another wave of newly birthed parasites crawled into the vents, slipping through a grate in the office where Rose was draining the cum from an unfortunate member of the staff who had come looking for someone. He had been all too happy to abandon his search in favor of fucking the broodmother, a role he would fill until his body gave out. Over the course of the next few hours, hundreds of parasitic creatures crawled, slithered, oozed, and wormed their way out of Rose's mutated womb, the horde of small monsters spreading through the hotel in search of untouched prey.

Feel free to add your own chapters here if you want. There's plenty of people in a hotel...