For the episode entitled “Blood Of My Blood”, Bran had a lot more of his visions, including a cluster of images from the past. And one of the things he witnessed was the Mad King.
… yelling “Burn Them ALL!!”
This is nothing new. We’ve heard the story a few times, even from Jamie himself when he was with Brienne. So Bran’s vision fits into what we would expect. But one thing I never really asked myself was…
“What made him mad?”
What if “Burn Them ALL” was about the White Walkers. Maybe he had visions as well, not as intense as Bran’s but something that showed him that the White Walkers were coming.
We know FIRE kills the Undead. So he could have been talking about that.
Maybe his visions drove him to such insanity that he saw everyone as a White Walker that needed to be burned.
OR
Maybe he saw that the dead were turned into an army and did a preemptive attack to save himself by having everyone killed by fire. After all, if everyone is dead, there is no one to “turn”.