Plot Twist: It’s no one
And,they’re just testing his allegiance

They're all synths.

One's the poster girl of the series and the other is a seemingly important character. Neither of them are dying regardless of who's who.

Isn't it Makoto?

Like follow my reasoning here...

If these guys are planning a rebellion wouldn't the best solution to be to root them out with a spy?

Wouldn't management see fit to plant a poison pill of sorts for the rebellion to swallow, a sleeper agent that thinks its not an agent, so as to root out all opposition to their goals?

Think about how many times hes been outed as being in the know, publicly, and yet he hasn't been turned into a puppet. Also puppet hammer face (that's what im calling the puppet in the tunnel) did not fatally stab Makoto despite it's freakish strength? How convenient is that?

Now I am not saying Makoto is actually on the bad guys side, I am just saying that he may not know that he's the sleeper agent until it's too late.

Can't be the kid. He intentionally killed Ai 500+ times for his own purposes. No way would that fly with the 'top brass'.
Doubt its the girl. Her agenda aligns in keeping Ai alive, but wouldn't make sense for her to go out of her way to inform Makoto of the situation he was in.... unless, of course, Makoto's the ACTUAL key and Ai is the red herring and method to hook him into their plots, but there hasn't been any clues that would point to such a conclusion.
However both the whole gun-pointing part and the friend not knowing Yukiko throws both possibilities into the mix. I'm gonna go with @TwilightFaze 's idea that it WAS the girl, but then she doubled back against them for reasons.

100% AI

Just kill the shota, enemy or not 😀

It's a test. Neither is the traitor.

If the kid were the traitor it would be too obvious. If Yukiko were the traitor her entire approach from the beginning would have been different.

If these guys really knew for sure one of the two were a traitor, that person would already be dead.

The better question is who has the more glorious rack, Yukiko or Hana.

One of them is a manager, but we are not even sure if all of "them" have been shown/covered up in the CCTV feed. I don't think the author is going to either sacrifice a child genius, or the first busty girl, and will instead save both of them, in several different possible ways.

It's the girl.
Remember when she told him to meet on the train and he almost got turned intoa puppet?

If we're going with cliche route, it's the boi.
if we're going with the "twist" route, it's the girl.

I choose the girl, I think.

Just wild assumption, the Ai girl is the one 😜😜

Obviously the girl unless plot twist it's the guy

manager best girl

It's the girl

there always has to be some kind of an organization, doesn't it

thanks for the chapter!

Hard to say. Probably tiddies is one of the manager. Baiting someone with the baits to bait the rebelling manager.

@wankerLin: That's extremely unlikely, but dear god I wish that was the case. That would make for an AWESOME twist!

The MC is the real villain, he just doesn't remember cause that's all the cool villain do.

Shit just got real...