If there was ever a time for everything to hit the fan in AMC's zombie horror/drama The Walking Dead, now in its third season, it came during Sunday's night most recent episode, "Killer Within."

“Killer Within” began with an unknown figure drawing walkers to the prison and cutting the locks, which spelled major trouble early in the episode as Rick (Andrew Lincoln) and company were out in the prison yard when walkers soon overwhelmed the group and sent everyone on a mad dash to safety.The results were devastating and lead to the deaths of two original characters.

In the scramble, T-Dawg (IronE Singleton) was bitten, but before he transformed into a zombie he lead Carol (Melissa McBride) presumably to safety, although she was not seen again in the episode. The episode’s main event, however, centered around Rick's wife, Lori (Sarah Wayne Callies), who had to give birth just as the zombies attacked. She experienced serious complications, and Maggie (Lauren Cohan) was forced to conduct a fatal cesarian section. After Maggie cut open Lori’s belly to rescue the newborn baby, Lori's son Carl (Chandler Riggs) had to shoot his own mother to prevent her from coming back as a walker.

In a pivotal scene Rick and the two surviving inmates from the prison, who Rick and company were trying to decide whether to kill, banish, or allow in the group, rushed to the control center to shut the prison gates. But Rick was attacked by Andrew (Markice Moore), a prisoner he could have killed in episode two, but instead decided to banish instead. Big mistake. The walkers didn't do the trick, and it was Andrew who led the walkers to the prison and to this horrible predicament. As Rick was attacked, one of the inmates, Oscar (Vincent Ward), shot Andrew and showed his loyalty to Rick, but this was only a small win compared to Rick's major loss of Lori. The episode ended with Rick feeling horrified that he left the door open for Andrew to wreak such havoc when he could have just killed him instead.

For her part, Sarah Wayne Callies was not crushed by her character’s exit, but rather felt it was necessary for the well-being of the show.

“You don’t take a job in acting at all expecting 25 years in and a pension,” she told EW. 
“You certainly don’t take a job on a show called The Walking Dead knowing your character gets iced in the book and think, I’m safe.’ ”

It will be difficult to match the tension and tragedy of this latest episode, but stay tuned next week to see how our favorite zombie apocalypse survivors fare in this show that keeps getting darker and darker. The Walking Dead airs Sundays at 9 p.m. EST.

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