The premiere episode of Game of Thrones Season 8, like most first episodes of the series' last seven seasons, was a mix of table setting scenarios mixed with reminders of where different characters stand. There were 12 reunions all told, from Jon and Arya, who hadn’t seen each other since Season 1, to Sam and Jorah, who haven't seen each other in all of four episodes. But by far, the most dramatic (if brief) was the final meeting, where Jaime rode into Winterfell and saw Bran again for the first time since he pushed the kid out a tower window at the end of the Season 1 premiere.
But Jaime's meeting with Bran may not be the thing that puts him in the most danger, despite his obvious trepidation that the Stark family knows the truth about that fateful day when he chose to attempt to kill a 10-year-old boy to protect his sister’s reputation. Instead, the danger comes from meeting Daenerys Targaryen, a character he's yet to have a proper introduction to, despite having charged her and her dragon on the Field of Fire last season.
Game of Thrones spent most of the Season 8's first hour re-establishing where characters stand. But it also reminded fans that Daenerys still has a major issue as a queen and ruler: her inability to bend, for fear of looking weak. In Season 7, both Tyrion and Varys expressed concerns about it, concerns which came to a head after she burned the Tarly family where they stood, instead of giving them a chance to reconsider their willingness to bend the knee to her rule. Now that choice is coming back to bite her.
Sam's discovery she killed not only his father (who he never liked very much) but his brother, who was a good-hearted soul just trying to impress his father until the end, was a catalyst. It drove him to tell Jon the truth about his parents and push him to claim his heritage as Aegon VI Targaryen, ruler of the Seven Kingdoms.
Jon protested to Sam that Daenerys was a good ruler, and her unwillingness to bend was part of what proved she was the right woman to rule the Seven Kingdoms. But Sam countered Jon was a good king because he was willing to bend, recognizing when he should put aside his pride for the good of his people. He bent the knee to Daenerys so she would ride north and fight the Night King. Sam asked, "Would she do the same?"
Jaime’s arrival allows Jon the opportunity to see if Sam is right about Daenerys. Before he was the father of Cersei’s children, before he was the man who pushed Bran out a window, Jaime was "The Kingslayer." He murdered Aerys II Targaryen, the last Targaryen ruler of the Seven Kingdoms, as he sat on the Iron Throne. By Jaime's own admission he didn’t do it out of lust for power, but fear. Aerys was called "The Mad King" for a reason. As Rhaegar fell to Robert and the Targaryen regime collapsed, he screamed "Burn them all," driving the then 19-year-old Jaime to kill him, in terror the King would give the order to burn King's Landing to the ground, killing millions.
Daenerys knows her father was mad, but still, it was her father. She was raised by her brother Viserys to dream of the day they would confront the Kingslayer after taking back Westeros and meting out justice. The fact that Viserys was emotionally unbalanced as well didn't help those stories either.
With Jaime now in Winterfell, having arrived with no Lannister army to back him up, and in fact bearing the news Cersei had betrayed her promise to Daenerys, Jon Snow and Tyrion, this could be viewed as a way to solve her problems with the Northern people. Most of the Stark bannermen hate the Lannisters, as do most of the common folk. Add in Jaime being the reason Bran is sitting in a wheelchair, and Jon, Sansa, and Arya would easily side with her too. One show of strength with Dragonfire burning Jaime alive will have everyone bending the knee, right?
However, it would also prove Sam right. It would also be a selfish, petty move, killing a potential ally for a personal reason. It's the kind of thing one would see advocated by Cersei. It would also show Daenerys to be a woman who murders because she can. As Sansa observed last season, it might be easier to cut off the heads (or burn) all who oppose you, but it doesn't make you stronger.
The real power move, in this case, would be for Daenerys, despite having the ability to burn Jaime where he stands, instead staying her hand, allowing him to live and fight for the side of the living when the Night King arrives. Jon may not admit to anyone what he knows about his heritage yet when the Starks and Targaryens sit down and face Jaime Lannister's arrival. But Sam’s words will stay with him, and he’ll be watching. If Daenerys chooses wrong, her relationship with Jon and her chance to rule the Seven Kingdoms without another Targaryen clamant opposing her could be over before the Night King even arrives.