The Walking Dead The Walking Dead

Reunited and it feels so... awkward?

When heroic Deputy Sheriff Rick Grimes (Andrew Lincoln) strolls into survivor camp on Sunday's episode of The Walking Dead (10/9c on AMC), his wife Lori (Sarah Wayne Callies) must balance her joy at Rick's survival against the guilt she feels for starting a relationship with Rick's best friend, Shane (Jon Bernthal).

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Although Lori had reason to believe that Rick, who was in a coma when the zombie apocalypse began, couldn't have survived, Callies tells TVGuide.com her character's relationship with Shane doesn't involve the head or the heart.

"I don't think she's feeling anything or thinking anything," Callies says. "If you were to listen inside her head, all you'd here is 'Ahhhhhhhh.' These people have been living at such a fever pitch, with such an extraordinary amount of adrenaline and terror and loss and grief, and I don't think there's a lot of analysis going on. Reasonable logic is like sand — it's running right through her fingers.

"There are moments when we are behaving much more like animals than people," she continues. "I think Rick's return is something that gets Lori to try and pull that humanity back in."

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Shane carries an equal amount of guilt, as it becomes clear that he perhaps initiated the affair and has now assumed a father-figure role for Rick and Lori's son, Carl (Chandler Riggs). But Bernthal believes Shane's motives were initially noble.

"Shane felt like part of Rick and Lori's family before the apocalypse," Bernthal says. "Shane did the first that came to him naturally, and that was to get Lori and Carl and lead them to safety. When Rick comes back, it's not a love triangle. I like to call it a ridiculously complex relationship that really the four of them are going through. There's just so much love that each of them have for each other, but also so much betrayal and jealousy."

That jealousy isn't necessarily tied up in the affair. Rick's return also raises some sticky questions about leadership within the camp. "I like to think of Shane as Rick's pit bull," Bernthal says. "He's the No. 2 guy and that's where he operates at his best. But when they apocalypse hits... Shane is thrust into this position of authority and leadership.

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"When Rick comes back, Shane falls back into that No. 2 position," Bernthal continues. "The only problem is he's now had a taste of what it's like to be No. 1. I think that it's horrifying and I think it's intoxicating [for him]. Shane starts to question Rick and, more importantly, perhaps Lori does at times. There's this vying for support, and it becomes political."

When Rick decides to return to Atlanta after spending only one night at the camp, it's easy to see some of the problems that plagued Rick and Lori's marriage before the apocalypse. "Rick's decisions aren't always great decisions," Callies says. [Shane and Lori] want naturally to support him, but there are moments where the stakes of [Rick] being wrong on this one could be pretty high."

That unrest will eventually spread throughout the entire camp, as the strange bedfellows find themselves fighting a war with one another that is almost as brutal as the war against the zombies. But can the need to survive outweigh petty squabbles?

"These are people who would've hated each other before, and they are forced to live together and really resent it," Callies says. "And then all of a sudden, when everybody's in danger, the person you were fighting is who just saved your life. There's a sense that when things are as bad as they can be, you've got to put it all aside. There's a need to leave all of the things that we think separate us behind in order to not turn into monsters — in order to survive long enough to have another generation of beating hearts on the planet."