She just realized that they, or at least Hinako, have serious romantic feelings for one another and it's not just an idle little crush or something more platonic.
Something stupid is going to happen. Because something stupid has happened basically every chapter for the last twenty chapters. How does an author lose the plot?
My suspension of disbelief could handle Maria somehow being this super skilled psuedo assasin/spy type. But it can't deal with basically everything around Okaya and Ajiki. The bomb plot, the stabbing, all of this - this series really went off the rails in a bad way.
Why would you think I'd want to fix Souko? Souko is the right kind of broken and pathetic, I just want to pat her head and tell her it's alright, I never expected her to succeed.