At Hershel's request, Thomas' body is thrown to the zombie hordes outside of the prison where it's devoured by the undead masses.

After Thomas is killed, Dexter and Andrew try to kick out Rick's group, resulting in walkers flooding the courtyard.

During the struggle, Rick shoots Dexter in the head, covering it up as friendly-fire, and Andrew surrenders, running outside the gates to die.

The prisoners' debut in "Sick" where they witness Rick amputating the lower portion of Hershel's leg after he is bitten by walkers.

Tomas brutally kills Big Tiny after he is scratched by a walker, despite the latter's pleas that he doesn't feel any effects.

When the prison's sirens sound off, Oscar explains that the backup generators are powering the alarms, and takes Rick to shut them down.

During his plan to rescue Glenn Rhee and Maggie Greene, members of Rick's group, Oscar is shot dead by a Woodbury soldier.

At the prison, Axel soon tries to win the favor of the group by trying to stir up conversations and takes a liking to Beth and Carol, flirting with them both.

No matter if he's allowed to stay or not, Andrew later betrays the group and initiates an attack to take the prison for himself as in the TV series.

Depending on the player's choice, Andrew either directly kills Carol or causes Lori's death in childbirth with his actions.

He described him as "a gregarious Southern redneck-biker type, who has big heart" and "a sense of compassion for his fellow man, but he is not as meek as he might appear, and though he has had to survive with four other hardened criminals, sans Oscar, this brave new world is something entirely different for him.

[4] Lesley Goldberg of The Hollywood Reporter noted that in "Killer Within", Rick's decision to lock Andrew out "amid a sea of walkers came back to bite the group in a major way".

[6] Ted Pigeon of Slant Magazine described the episode's opening sequence: "With its dreamlike, foggy setting and a conspicuously waist-down perspective of the saboteur, a peculiar sense of disconnect underlines the implications of what's being depicted.

Moreover, the pre-credit sequence lends insight into how the episode amounts to a particularly poignant, if also problematic, entry in the show's run.

"[7] Pigeon also notes that the opening segments of the episode "establish the origins for the ensuing chaos while going to painstaking lengths to conceal the identity of the man that caused it".

[7] HitFix writer Alan Sepinwall commented on Andrew's sabotage of the prison: "on the one hand, it helps justify Rick's decision to chase after the little guy in the first place.

"[10] Los Angeles Times columnist Laura Hudson observed tribalism as a trope in "Killer Within", which she ascribed to the reluctance of Maggie, Rick, and others in the group to allow Oscar and Axel into their clan.

Hudson noted that these characters had been severed from the cultural and social fabric of their past civilization for so long that they have reverted to "traveling in a small, tightly knit group, hunting and gathering, and regarding anyone who isn't part of their it as a deadly threat.

"[6] Zack Handlen commented in his review of "Made to Suffer" that "Axel's enthusiasm for getting laid is sending off all kinds of creepy vibes, just the way he got real interested when he found out Beth was 17 could be a bad sign.

Club, commented that in his earlier appearances, "Lew Temple managed to invest Axel with a certain mangy charm, and he really blossoms in this episode; when he's chatting up Carol and shining a little white-trash charm, I found myself thinking, "Shit, I'm glad this guy's around," which is a thought I haven't had about Rick or Glenn or Maggie or Hershel in living memory.