Cheese in the Trap Season 4???

Anyone understand the flashback in chapter 100 to 106??? When Sul and Jung had to volunteer at some place. However the way they treat each other so cold...I confused. Is this flashback before they were together or recent memory?? If it is before they were together, why did Jung "held onto"  then slowly let go Sul's hand as she was talking in her sleep, like they were broken up lovers????So confused anyone had any ideas?

It's why Jung decides to treat her nicely and ask her out. From what I've gathered this is a flashback to right before Jung treats Sul out to diner (convenience store lol). One of the flashbacks (don't remember when) has Sul, Jung, that dude Jung is close friends with (kang-something), and a couple of classmates discussing ideas for a festival/fair. Sul suggests an out of the way building and Jung shoots it down kind of harshly before kang-whatever supports Sul's ideas with back-up. Anyways, back to this flashback that you're talking about. Sul is carrying heavy stuff (for the festival/fair thing) without anyone helping her, and Jung realizes something and suddenly switches the way he'd been seeing her. Afterwards they get stuck together (???) in a warehouse/something and Jung spends the time contemplating. Afterwards he decides to get to know her, so he invites her to the convenience store.