Ok so this is what is going on....
The Leader of the town (Glasses guy) was a researcher who betrayed his mentor by shooting him in the leg all because he didn't want his daughter to be left all alone. He stole his research and vaccines. He later on came to a town where the seme (doctor) was at with his previous lover (black hair woman) who is now dead. He decided to stay there and eventually became leader. He got the doctor to work with him in testing out the vaccine. The leader caught a zombie who was actually Dajeong and tried the vaccine on him. This is when the scene from chapter 1 happens and the doctor is supposed to kill dajeong since the vaccine "failed" but instead doesn't kill him. The leader (glasses guy) thinks the zombie is dead...I guess he didn't recognize dajeong as the zombie and that is why he checks to see if he has that wound.

I need to know what"s going on, i'm confused. It looks like red head used to work on vaccines as well? Was the black haired MC one of their "test subjects that they could just kill"? Did brown hair MC test on him too? It didn't seem like they knew each other, he just refered to him as "a doctor" when he and his daughter got to town. I want to like the red head because of his daughter-complex, but i really can't look away from the whole "shoot an innocent guy's leg to get away" scene. I mean, i UNDERSTAND it, he knew he had to live to raise his daughter, but it's still messed up. It feels like instead of trying or really even searching for another method, he just went with the guaranteed result. The dude was eaten alive... I don't hate his daughter anymore, she was just jealous/heartbroken. She's being reasonable now. Nice character development from her. I really hope he doesn't start shit, but when he said "if it's not the case you'll have my blessing", it implied they WONT if it IS the case. I guess dating a former zombie is a line for him?