Sorry to raise such an abrupt question on such a late date, but there seems to be a little mistake in the translation. I noticed that when Jinju came to pick up Doyeon home, Professor Hwang just said that you were the first to come here and the Korean lines refer to "그쪽 이 1 번 이던데 , 가족 이신가 ?", which directly means "You are the number 1, are you family?". Since Professor Hwang didn't call many people to come here, I tend to interpret that "number one" as "the number one person in the address list" or "the first contact" (the first person to call when there's something happening to the phone's owner).
All the things above are just my personal views, and maybe there's something wrong. Since I am a non-native English speakers, there may also be some mistakes in my expressions, please pardon me for this comment which seems to be strange.
