Vorden couldn't believe it. Jack Truedream was still alive and was out there somewhere. He truly believed that if the Blades were involved, he would have been dead. If not dead then at least turned into one of the Chained to never be able to leave the island again. It was the first time he had heard someone was able to get away from Hilston like that, and now he understood the anger on his face.
As for the reason for not remembering who he was initially, it was because Hilston remembered strong people and not cowards. There wasn't a doubt in Vorden's mind that Jack was running away using some type of trick rather than fighting his grandfather.
Still, the military didn't know where he was, and it looked like the big three didn't know either. He was either still hiding out there, not wanting to come out (which was understandable after what the Blades had done to his city), or another family were keeping him in secret. It truly might have been a game changer if that was the case.