poor knowledge and realism of zombies
as most know, zombies are god-damn cross country world record breakers for the 100m dash, they can run but albeit sorta about 50% extra of their walking speed, another note it that the target s are too small and your team mates can hit shit makes this a poor game, and just for plot hole laughs, why don't they just bomb the shit of of the unsecure wall or actually build a blockade there or something, christ those 3 guys a dimwits to stand there without even a proper team (hey john, look theres some zombies running at us. yea, lets shot our guns randomly at them until they eat our brains out.)