Here's a quick summary of their conversation. DG and Jiwon go to a video arcade, DG wins the game they are playing, and Jiwon being competitive wants another shot at winning so they try a different game. The game involves using a gun, so Dong-gyun asks Jiwon if this is the first time he's held a gun, or something like that. Jiwon says that he was in the army, and was part of the search squad. DG seems impressed and says he was only an officer. Jiwon tells DG to stop gawping at him and play the game. They defeat the zombies and high five, which they find embarassing as I think this was the first time they have even touched hands.
Anyway, Jiwon stomach is rumbling so DG persuades them to continue their date, He says knows a place that does a cheap meat, with infinite refills. DG eats a lot, and calls for his 4th bowl of rice. Jiwon thinks such gluttony is horrible, seeing as the meat is poor quality. He also says he is the type of person that gets "fat from just drinking water" and is basically envious over DG's metabolism. Jiwon has flashbacks to eating salad, weigh training, scales and watching mukbangs of people eating food he won't allow himself to eat. Basically his weight must be an insecurity and hopefully this is showing DG that Jiwon is just a person like he is, with his own struggles. Jiwon then goes on to talk a bit about MD, then DG says that "he is happy to just spend time with Alex", note that he calls him Alex and not by his actual name.
That's all I can remember for the moment, translations were from a google translate app so not the most reliable.

me watching them have sex in every chapter: oh that's cool (づ ̄ ³ ̄)づ
vs
me realizing they're finally going on a date like a pure couple: O MY GOD ITS FINALLY HAPPENING JDFNCJEFBVNVR (ノ≧∇≦)ノ (≧∀≦) (๑•ㅂ•)و✧