"He's a nut but yeah, it could definitely be worse." 

Basil drops down out of the rafters again. "Congratulations, you're all too paranoid to have actually believed I was gone, which successfully disincentivized me from spying. Also, you reached a mutually agreeable distribution of resources. That was scheduled to potentially take the rest of the class period, so you can all leave early, or stick around and discuss the subject more if you haven't anything more interesting to do."

....huh. 

Not that she wasn't already 100% sure they were being watched, but it's weird that he'd tell them that being paranoid worked. 

"Cool," she says, and leaves. 

Once Nat's left and he won't be the first to stand up, he'll leave too. 

Bernard is surprised Basil isn't more annoyed at them and thinks this whole "you can leave early" thing might be another trick, but when nothing happens to Nat and Sasha he exchanges a glance with Jennifer and they leave too.

The next time class meets, there's a tall partition between the two desks on the left and the two on the right. Basil is sitting in a mouse-sized armchair in the middle of the desk.

....kay. 

Sasha picks a desk more or less at random. 

Nat makes eye contact with him when she walks in the room and then sits on the other side of the partition. (Basil saw her play favorites last time. She's sort of curious if he'll independently figure out gangs or if he'll think something else is going on.) 

Jeanine looks deeply annoyed that Nat has messed up Bernard's ability to sit behind her. She takes the seat behind Nat and Bernard takes the seat behind Sasha.

Well, maybe if Jeanine and Bernard wanted to pick their seats they should have gotten there first. 

Well yeah, she's not going to ask her to move or anything. She did get there first. It's just inconvenient.

"Good morning, everyone!" Chirps Basil's amplified voice. Today we're going to be playing a game in pairs. Imagine, if you will, that you and the person across the partition from you have been arrested. The police give each of you a choice: you can testify against the other person, or remain silent. If you both remain silent, you both get one year sentences; if you both testify, you both get two year sentences. If only one person testifies, that person goes free and the other one gets three years. Now, without giving a decision, do you all understand the problem?"

Bernard and Jeanine both think about it for a bit and then nod.

Nat and Sasha nod too. 

(Gangs make this problem easy. He's glad he's across from Nat and not from one of the others; he knows what she's going to do.) 

"Excellent. Now, as you have guessed, we will be playing the game across the partition. Please write down on a piece of paper both your decision and your reasoning, and what you expect your partner's decision and reasoning to be."

Nat writes down "Testify, because I'm an asshole." 

Sasha writes down "Testify, because I know Nat." 

"Keep silent, because I'm not going to hurt Bernard and he wouldn't hurt me either."

"Keep silent, because Jeanine won't testify against me and I won't testify against her."

"I see you've all stopped writing. Now, turn your paper over and do the same exercise with the person diagonal from you. Bernard and Nat, Sasha and Jeanine."

"Keep silent, because I don't know Sasha and want to give him the benefit of the doubt in the hope he does the same for me."

"Keep silent, because if this were real Nat would find some way to get revenge."

"Keep silent, because I'm pretty sure Jeanine isn't Nat." 

"Keep silent, because fuck the police." 

"Capital! Pass your papers up to the front. And you can put the partition down now if you like, we're done with it."

(Jeanine gets up and puts the partition against the back wall.)

Basil reads the responses and makes a sound that is probably what a mouse sounds like cackling with glee. "Excellent, excellent, . Everyone ended up cooperating with each other, with the exception of Nat and Sasha, so let's go over that first. It appears that Nat picked "testify" as, let's call it an intellectual exercise." (This is clearly politesse for "to troll".) "And Sasha, you predicted she would do this and that lead you to do the same?"

"I did, yes."