Lan Wangji doesn't know what would come next. He doesn't have answers. He was just as grief-stricken, ridden with guilt and regret that he too wasn't able to stay by his side. A part of him wonders if Wei Wuxian ever going to come back and if he dies in this one, what would that mean if they ever return home? Personal experience taught him that if a dead person ever coming back, it's a slim chance, a miracle.

No words are needed, silence is necessary. He can't offer words of comfort. They can agree that Wei Wuxian is special to them. Shuffling into the train, and finding a seat, it's going to be a long journey to the city, leaving the tragedy of the event behind. Lan Wangji felt a measure of relief that they finally leave, but at the same time, the guilt and grievances of Wei Wuxian's death weight heavily on his mind.