With their inability to focus on a good thing (John Dorie, maybe Morgan) the writing team have conjured up a baddie out of thin air since we don't have enough of those with zombie hordes or ambivalent truckies and the core team fighting their own demons.
So lets introduce sadistic Whoppie Goldberg clone. is she mad, why is she insane?, what's her motivation and what is her end game? like all bad American cinema these things just are, don't question it, don't look for reason logic or motivation, accept it and look forward to their demise after squirming at a few episodes of them being illogically cruel. At least she's weaponising zombies again though.
This episode was so decidedly average and wheeled out so many tiresome well worn tropes (radio signal won't work, signpost changed, sickness, easy kill zombie left and becomes a threat when they least expected it but we oh so expected it, etc etc,... yawn). The jam is spread so thin on this series it's like eating a loaf of white bread.