Prediction: Yuki confront Kurumi. Failed to convince her. Halfway through the talk, the melee leader dude was taking Miki as hostage and plan to run away to the company place to find a cure. Kurumi save Miki with her zombie powar. Miki successfully convince Kurumi to stay. The team heads to the drug company. Found the cure for Kurumi. Time skip. Kurumi and Miki marry in near future (because screw the government), make an awesome zombie fighting duo.
(Yuki follow Negu-nee path to become a high school teacher. While Rii becomes an elementary teacher to recover the hole Ruu left behind her. The two will hang out late after school and have their own things)
This sounds legit. I love the Kurumiki endgame part, if any pair is endgame, Kurumi and Miki would make the most sense! I think up to this point, Miki is the only one who could tear down the walls Kurumi is building around herself. I know she's doing it to protect the people she loves but she needs consolation and she needs to open up.
I'm a little bit scared about what might happen to Miki though... I don't want her getting harmed!!! I also don't know what Takahito's deal is and I just couldn't care less about him. But if he turns out to be infected and bites Miki, I will throw a fucking fit!
I think that if they don't have a "happy ending", it will eventually end with Yukki being "the last man standing". And oddly enough I think the first one to go would be Rii-san just because of the state she's in right now. She's too far gone and it's just really sad/depressing, I don't think she's in the right state of mind to survive in an apocalypse.