http://www.l4d.com/comic/comic.php?page=138 the soldier would have to of used a gas mask so he wouldn't be infected. Unless that picture was a joke that flew way over my head.
Also, has anyone ever noticed that Bill probably would have died anyway even if he didn't set off the generators? I mean he fought off zombies and had just as much strength as the other survivors, might have mean't the surgery he got was for something pre mature that could've developed into something life threatening. But I am probably late as hell.