Plot hole: When the survivors first make an attempt to break out towards the station they kill numerous assailants at close quarters and yet only one of them (Uno) is infected. There must be dozens of the parasites floating around, enough to infect them all.
Plot hole: When the Police first enter Shining Canyon, they make a point of mentioning why they don't have to wear a full breathing mask, because of the goggles they wear. (!) Later on however, several people who are not infected are not wearing the goggles, so they shouldn't be able to breathe.