When The Walking Dead surprised fans with a sneak peek scene from the Season 7 premiere at New York Comic Con, you could hear the screams and moans of horror from fans rocketing through the Theater at Madison Square Garden. Not just once, but multiple times throughout as they watched the villainous Negan (Jeffrey Dean Morgan) and a defeated Rick Grimes (Andrew Lincoln) face off after the death of one of Grimes' gang.

The scene is extraordinarily tense, and not just because we still don't know the identity of Negan's victim (or victims). "It's the first time we've ever seen Rick Grimes scared in the entire series," director Greg Nicotero told TVGuide.com over the phone. "From Episode 1 onwards, he's always been in control. He's never been on his knees in front of anybody. Everybody there, their power has been completely taken away -- and they're all powerful people."

For those not totally up to speed, after the Grimes Gang killed several members of Negan's gang of thugs, the Saviors, Negan marshaled all his forces to drive Grimes and 10 other members of his team of zombie survivors into a clearing in the woods. There, Negan forced them all to their knees and explained that he was going to kill one of them in order to show he means business. And then he killed someone, off-screen, though we don't yet know who.

When the sneak peek picks up, Negan has already murdered someone, and a shaken, rattled Rick -- the right side of his face splashed with blood -- is still on the forest floor.

"He's still defiant," Nicotero said of Grimes' emotional state in the scene. "He's still arrogant, cocky. He looks at Negan and says, 'Not today, not tomorrow. But I will kill you.' "

Which seems like a bad idea, given that Negan has spent nearly 10 minutes in the Season 6 finale explaining how he works. "Clearly, Negan's show didn't have the desired effect on Rick," Nicotero added. "So Negan's got a lot more work to do."

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For Nicotero, directing the scene was a huge challenge. He's tackled everything from the moody, dreamlike episode in which Chad Coleman's Tyreese slowly died of a zombie bite, hallucinating past members of the cast as he expired; to more action-packed episodes like the Season 6 premiere. But for the multi-hyphenate (he also manages the effects team and is an executive producer on the show), getting into Rick perspective was a new and difficult experiment.

"We start in that extreme close-up of him on the Season 7 sneak peek," Nicotero recalled. "We're right into it, in his eyes, and into Negan's eyes. We're right there. We don't cut wide. You're there, listening into what they're saying. That's the way Rick's perspective is tremendously important."

He added that most of the premiere episode is from Rick's perspective, as well, which was challenging as both the characters and audience need to experience the full weight of the death. "You need to get into other people's heads as well to be able to experience grief and sorrow and fear. So it was a very, very difficult episode to wrap my head around when I got the script because of those perspectives and how the events play out."

As to how exactly those events will play out, beyond what we've seen in the sneak peek? We'll have to wait until the show returns to find out just what's in store for the surviving members of the Grimes Gang (though we have a few ideas).

The Walking Dead returns to AMC on Sunday at 9/8c.