He does vaguely remember water ghosts at around this time. Maybe it was just a matter of a subtle change in Jiang Cheng's behavior causing Wei Wuxian to pass through a walkway a few seconds early or later than normal. It is true that his brother would follow Lan Wangji. Inexplicable. The man is as uninteresting as a rock. But it isn't strange for him.
"Go back inside, both of you. Zewu Jun was looking everywhere for you, Lan Wangji," he says. "Don't make your brother worry about you."
"And A-Jie was worried too," he says, looking at Wei Wuxian. The memory of her, running through a battlefield to try and find Wei Wuxian. Shouting for him, oblivious to the danger. "Stay where you're supposed to and don't make people have to search for you."