Start from the beer scene.
WooYoung tried to talk SeYoung into drinking more beer.
SeYoung's head leaned toward WooYoung: "What are you up to!?"
Show WooYoung was smiling and looking at SeYoung while She was laughing.
WooYoung's voice as narrator: "I will take take care of you."
Show bed scene.
WooYoung's voice as narrator: "For our hot summer!"
MCs in the studio: "WhatTF just happened in the last part?!" "What's THAT!!"
They didn't actually show what WY said when they were on the bed.
They just cut WY's "For our hot summer!" (from other part I think) and put it as narrator for that.
MBC editor did the same thing on "I can't live without you" on jebu island preview footage.
What they show on screen and what you hear from WY are not from the same footage.