This kid is really trying to make himself useful. 

"What is it, Tintin-gongzi?"

"I assume you have noticed that the Anglo contingent is... more confused than they might usually be. This is because the Chicago enclave was somehow destroyed, or so they believe, and so a significant number of their new freshmen are from mundane families. I learned this from a girl, the one wearing silk, who bartered with the newcomers for their hair."

"That's very strange. I wonder if there's a connection to the disappearance of Song Lan."

He doesn't want to think there are dozens of kids who are easier prey than Wen Ning but that's what he thinks. None of the kids deserve to die but only some of them are his.

"The -" he starts, before he can stop himself. (Some shoved-under-a-rug part of his brain is saying mystery? Mystery??? and he would like it to stop.)

"Shanghai enclave was supposed to have six freshmen come in this year. It had five. Song Lan was present at the induction and wasn't present at the cafeteria. We don't know anything else."

mystery!!!!

"I am very sorry to hear it. If I learn anything that could be related I will certainly tell you - I do not imagine anyone would have a list of the people who tested in, that would be extra weight, but if anyone would have - no one would memorize dozens of names for so little reason - I am sorry, you must have thought through this already."

"There are no obvious confused mundane-born wizards wandering around, I looked. Perhaps the spell failed to grab him for some reason." Perhaps someone killed him. 

"Oh, I was not assuming that he was untouched for no reason. I would assume first that someone had surreptitiously weighted his backpack or some similar tactic in order to induct someone who had not passed their test, in collusion with that individual. They would not be confused."

"A reasonable line of thought. It's well worth investigating. The Shanghai enclave will not take such behavior lightly."

"Of course. Thank you for explaining the situation, Lan-gongzi - I hope to help in some small way."

"If you discover anything of interest the Shanghai enclave will be most grateful."

"I fully understand."

That's a dismissal. Tintin vanishes back into the masses, determined to uncover the heart of this mystery.