“Typical,” said Mariko. “The Corps took over somebody’s business and turned it into a den of lies.”
“I take it you don’t approve of Heida’s methods?”
“How could I? She’s conning these people and scaring them with monsters that don’t even exist!”
“Then let’s promise to not take the easy way out. We’ll see what we can really do to help people. No taking shortcuts to put on a good show.”
“Hm,” I said, scratching my chin in contemplation. “I don’t think our hostess will care for that. She is our superior, after all.”
“When we have a choice, then,” she said. “Please? For me? I couldn’t look myself in the mirror otherwise.”
Mariko wants to force Heida to tell the truth: “Should we tell Mr. Maki? Maybe the Headmaster?” This is both unnecessary and dishonourable.
[Dishonourable] because it isn't a purchase or a war. Mariko is allegedly a pacifist, but isn't above threatening someone to get what she wants, as long as it's an "authority" doing the threatening on her behalf. Wants someone to wage war as long as it doesn't look like war. Typical pacifism.
Unnecessary because Mariko can't be fired for disagreeing with her superior in public. Doesn't have to even call it out as a lie - she can simply refuse to play along. "I don't see any evidence such a monster exists." Heida will get angry, but she's in a bind - either she allows Mariko to puncture the lies, or she removes Mariko from the situation where she has to play along with lies...which plays to Mariko's pacifism and isn't reasonably possible.
In these cases, the opportunity to revoke your consent from the illegitimate authority always exists. The only question is whether you take the opportunity. Whether you manifest your ideas as action, or discredit your own ideas with inaction.
Mariko has already won. It's merely a question of whether she accepts victory or not.
I personally have lost every shred of patience for those who make excuses. As we can see, Mariko is rejecting victory - she wants to play along with the superstitious peasants who she knows and accepts are superstitious. Novel authors feel obligated to uphold the local mores, after all.