Continuity mistake: When the lieutenant and the new guy that joined up in season 2 are in the hospital, he reaches for his gun, shoots, and...click. No ammo. The lady then pulls our her gun, slide fully retracted, finger not on the trigger and states "yeah, me too." Thing is - if the slide was already retracted from running out of ammo - wouldn't she already know? I mean, she holstered the pistol. More egregiously, every shot before this, her slide was not retracted, and the pistol was ready to fire, until now, when she suddenly has a retracted slide.
Continuity mistake: Towards the end a woman is walking towards the fence completely covered in blood and guts, we see close ups of her boots, trousers and hands all covered in dripping blood. In the next shot she is still walking but her boots and trousers are clean and the blood on her hands is very dry.