
I think it's definitely a flash back. It's followed by the scene in present moment, where Jihwa is sitting in the snow, in the same spot where he confessed to Seungho earlier. He seems to be recalling the past times and it's folllwed by him recalling what Seungho said to him when he confessed. Hence, the absolute heartbreak later in the chapter

I think it's the future, after Jihwa made a deal with SH.. my theory is that he let Nakyum go without hurting him, if Jihwa was allowed to stay by SH's side, and SH accepted it knowing that this was the only thing that he could do to save NK..
We know that Jihwa still had his topknot when he saw NK tied up, so him losing the topknot must have happened in the future. Also at the first scene Jihwa also thinks about their past, when they were at their worst, which is during their teenage years and thinks about how these two lords don't know anything about SH, so they must have met SH as adults..
However that scene is probably written with the intention of making it confusing to us readers, so perhaps it is a flashback after all..
Ok, so people are already arguing about the chronology of the events! Are the first panels showing Jihwa with short hair in the present or the past?? If it's the present it means SH thought NK actually ran away and he just let it happen. After being depressed for a while he probably went back to Jihwa and that's why Jihwa looks so fresh and happy and also explains those other guys words. We can also tell it's no longer winter time. But then, what the hell happened to NK all this time? Man, I am scared if it's really the case. I hope the author will tweet something to clarify!