[Warning: This story contains spoilers for the sixth episode of Game of Thrones' seventh season, "Beyond the Wall."]

For most Game of Thrones fans, the death of a dragon was a total blindside. For the Game of Thrones creators, it was a long time coming.

In their latest "Inside the Episode" video for HBO, showrunners David Benioff and Dan Weiss reveal that they have been building toward the death of Viserion, one of Daenerys' (Emilia Clarke) three dragons, for quite some time now. "The whole path of the show in some way has been trying to map out all of the episode end points, and with this one, it was the dragon opening its blue eye, and realizing that the Night King has finally gotten his own weapon of mass destruction," according to Benioff. No mincing his words on that one: the White Walkers getting their hands on one of the most powerful WMDs in Westeros and far beyond has been part of the plan for a long time. Pretty cruel, right? 

Actually, it gets even colder: Weiss strongly suggests that the "Eastwatch" crew of Jon Snow (Kit Harington) and the rest of his allies were gathered together and put in harm's way so as to misdirect viewers into thinking they were losing a fan-favorite character this episode — albeit not the fan-favorite character they expected.

"What was fun about the sequence — in an awful way to us — is up until the end, it's very close to one of those battles where all the good guys get out the other side more or less scot-free," he says. "But we knew that killing the dragon was going to have a tremendous emotional impact. Over the seasons and seasons of the show, it's really been emphasized what they are to Dany. We knew the Night King would see and seize this opportunity." 

"We like to think when the dragon dies, it's kind of a one-two punch," he continues. "On the one hand, you've just seen the horror of one of these three amazing beings like this in the world going under the water and not coming up again, and processing that. Then you're processing something that's even worse: when it comes back up from under the water again, and we see in the last shot of the episode what it becomes."

Consider both punches delivered, plain as day. If there's any consolation to the loss of the dragons (and we think there are a few), it's the fact that Jon and Daenerys are closer now than ever before, a fact that Benioff and Weiss outright confirm in their behind-the-scenes video.

"I don't think either one of them knew exactly how powerful their feelings were towards each other until these moments," says Benioff. "Just the notion of falling for someone... that involves weakness. It's not something a queen does. But she feels it happening, and he feels it happening for her. I think both of them are on unfamiliar ground, and especially because it's with an equal."

Watch the video below for more on Benioff and Weiss' thoughts on the episode, including what in the Seven Hells is going on with all of Arya's creepy antics.

Follow THR.com/GameOfThrones for all of our coverage leading up to the season seven finale.