The day was just like any other, with winter setting in and running its icy hands over the city to lower the temperature. People outside made paths in the snow so the sidewalk was dirty and slushy but at least passable. The streets were no better and in fact worse, with cars making a dirty mess of the roads and it was impossible for anyone to walk across without getting their socks or pant legs soaked. Inside the office buildings lining the streets, people went to work as they always did, begrudgingly and rather sluggish.
At the front desk of this particular office building, a young man had just arrived with a few packages and had stopped to talk with the receptionist, who wasn't giving him the time of day and was instead turning a peculiar little package in her hands. There was no name for the recipient, just the address of the building. The delivery guy gazed at the box while speaking to her, taking the opportunity inside the warm building to regain feeling in his toes. The heating was going out in his van and he didn't much enjoy the winter spent in the drafty hunk of metal. The receptionist used a small envelope knife to cut the tape on the box and pulled open the flaps.
Both the delivery man and the receptionist were greeted with a soft 'shhhhhh' and finished opening the box to find a container leaking a red-tinted gas of some sort into the air and the gas was spreading now, though the ventilation system whose duct was just above the receptionist's desk. Both exchanged panic glances, but nothing happened. They didn't know what to say, the delivery man stumbled backwards and left the building without thinking. Horrified, the secretary dumped the box into the garbage can and vowed not to say anything about it to anyone.
Men and women began flooding the hospital almost exactly three hours later. The sickliest of the bunch were already bleeding from their noses and eyes, coughing up blood. The doctors were puzzled, they'd never seen this kind of epidemic before and were clueless as to what had caused it. The healthiest of the group were placed together. That is where this group meets because, inexplicably, you are the healthiest. You came to the hospital for minor symptoms, similar to the flu, but you're not nearly as sick as some of the people you've seen being carried on stretchers.
Baffled, you begin to speak with the others in the room with you. They were all from the same office building...