From the Red Wedding to the Battle of the Blackwater, some of the most thrilling moments in the history of television now belong to Game of Thrones. In a new featurette, HBO explores some of the show's most pivotal scenes, which were also often the most strenuous to film. Among the many fascinating revelations made in this behind-the-scenes short is that while shooting the Battle of the Bastards, Kit Harington was given a safe word in the event that filming became too much for him.

In the video, longtime Game of Thrones camera operator Sean Savage shared that his very favorite scene to film over eight seasons was the moment during the Battle of the Bastards "when Jon Snow is forced to the ground and then trampled. And this seemingly immortal hero of ours looks like he's close to the end."

The scene wasn't entirely scripted, so when Harington fell to the ground, Savage stood over him and filmed from above as tons of stuntmen piled on top of the actor. In order to ensure that Harington wouldn't be injured, "we had a sort of safe word [so] that we could call it off at any point," Savage said.

"We had to see that the light closed up on Kit's face and at that point I just urged Kit to get off the ground and stand up again," Savage said. "And I think you can see that it is a true struggle."

It took a total of 23 days to shoot the Battle of the Bastards, making it one of Game of Thrones's most taxing scenes. However, we'll see an even bigger battle in the final season—one that reportedly took a whopping 55 days to complete.

But one important question still remains: What was Harington's safe word? Something tells us that's one question season 8 won't answer for us.