I'm rereading The Stand again for the first time in 20 years and that's the one thing I still don't get. I had assumed the reason they were struck down in their tracks (like Frank D. Bruce, who collapses into his bowl of soup and dies, and others described as still sitting at the lunch tables with drinks gripped in their hands) was because extreme measures were taken to sterilize the facility of the virus (like maybe evacuating all the air), but then when Starkey walks through before he commits suicide, other workers are shown to have taken their time to die, presumably of the flu. So what gives?