The hidden adlib in back door made Han think "Ah, the world is advancing"
At the end of Han's first part in Back door there is a small ADLIB which is translated to "Oh, it hurts, frick".
Han: When we made the guide for this song, we made the beginning part, and then the part it goes from the melody to the rap was too boring.
So in the adlib, we were wondering "Ah, what should we put in?" "Let's just put in anything for now", so we put in something provocative.
So we thought "No way...". We were thinking there is no way it will be released as it is" but it was released exactly as it was.
And I felt like "Ah, the world is advancing"
