Well, it's not absolutely nothing to work with. 

"Can you tell us what happened the day you arrived in Johannesburg."

.....What? Why are they asking about that. 

"- I don't remember exactly. I - I was trying to find the enclave, and - one of the floaty-cloud sort of mals came at me? And I felt it coming, in time, and then I had to drain a rat nearby to get enough mana so I could make it not come after me." 

"After you found the enclave. When a kvenlik attacked."

"....That wasn't the day I arrived?" Masozi says, confusedly.

"Okay. The day the kvenlik attacked. Tell me what happened."

Masozi manages to catch and stomp on several pointless digressions, which are emotions about that day rather than factual truths which he's supposed to say out loud. 

"....If I'd been stronger I could've saved everyone."

He thinks that's true? Probably? ....It might not be and now he's panicking about that. 

"Did you know it was going to attack before it did."

"....Yes?" 

"Did you lead it to attack Johannesburg."

What. 

"No! I - why would I - it killed people!" 

Neither Lan Wangji nor Meng Yao is in this room so there is no one here who can tell how profoundly Lan Xichen is radiating smugness.

"It killed people and got you a Scholomance spot. Right?"

"....I - if I'd been stronger I could've saved everyone - I, I knew - it was my choice - I could've tried to save everyone but I didn't...." 

"This spell does not work," she says tightly to Lan Xichen. "He is not actually answering the questions. I don't see how we can do this while he's under some kind of brain damage spell that makes him not answer yes/no questions with a yes or a no."

"You have better truth potion, we can wait for this one to wear off and give it to him instead. --What is first thing that happened when you knew mal was there?"

She says something quietly to Olivia, who stands up and leaves. 

Okay finally a question that doesn't hurt and doesn't twist his brain into circles trying to figure out what it means! 

"...I hid behind a -" he doesn't even remember what the obstacle was, "- behind a something? Might've been a car. I - checked how many wizard children were in range. There were five. I checked how much mana I had and - how many rats were in my range - I knew I could run away - I thought I probably didn't have enough to protect everyone..." 

Pause. 

"....There were two children on one side of the road and three on the other side." 

Annaka is incredibly incredibly not thrilled about letting Lan Xichen ask all the questions because when she asks them the kid refuses to answer and makes pathetic whimpering sounds; that's what trying to sneak something past someone looks like. But she grits her teeth, for the moment, because she's curious where Lan Xichen is going.

"What doed you do next?"

"I...... There were two on one side and three on the other? And I - couldn't go to both sides at once. ...The three kids were older. I - thought they had a better chance of fighting off the mal. ....And I guess I - I knew probably one of them was going to be going to the Scholomance. And I - thought about that...? And whether if they died I would get their spot."

"....And then I went to the side of the street where the two younger children were and I protected them." 

"You said that you knew the mal was coming in advance? How did you know that?"

“I can sense mals. If I’m close and I have mana. …S’not really my affinity, I had to stretch it, feeling where people are’s easier. Or animals. I - felt it maybe five seconds away before it came around the corner. So I - had to decide so fast…”

And he made the wrong decision, apparently, even if he doesn’t fully understand why or what, and now he’s going to die without ever seeing the stars again. 

His body is having trouble breathing from the effort of staying in control and not crying, but it feels like something that’s just happening, somewhere else. 

"--May I speak to you in hallway please?" he says to Annaka.

"Sure." They can step out.

"I'm sorry. He has bad reaction to truth potion. Mind control magic in general-- I'm not sure if New York has someone with affinity?-- is very very finicky, very easy to go wrong, and produces very weird results. I have forty-two variants on 'calm down' for this exact reason. Normally this high dose is very unpleasant but doesn't make someone this bad at answering questions. When I am on high dose of truth potion I just keep getting distracted by concept that lying is morally wrong and start crying about past lies I have told."