There are risks involved. As one of the future engineers explains, “The longer you stay in rapport, the stronger your influence grows on the host, and the more likely it becomes that your presence will be felt. Few hosts can deal with that perception.” The line echoes the Three-Eyed Raven's warning to Bran in "Oathbreaker." "Stay too long where you don't belong, and you'll never return." Ol' Three-Eyes insists that his student can't influence the past ("The ink is dry"). Still, he urges Bran to stop reaching out to his father. Perhaps because he did the same thing when he was a young man? Something forced Three-Eyed Raven to live inside the Weirwood for 1,000 years, "watching the world from a distance."
Bran is antsy to figure out life, and his ability to manifest before his greensight subjects should only grow stronger -- a deadly combination. A scene teased in a Season 6 trailer (now suspiciously removed by HBO) shows him toe-to-toe with the Night's King, a seemingly reckless move that could see the White Walkers descending upon his posse sooner than later. But if Bran's on the Luke Skywalker path -- OK, Joseph Campbell's Hero's Journey, for the storytelling snobs -- he won't wait for Three-Eyed Raven to wrap up training before he declares himself a professional greenlighter. He'll use his time travel powers to alter the entire history of Westeros.