This episode showed Joo Sang Wook's character as Dr. Kim Do Han weakness. The reason he is so mean and treat Park Si On roughly was because he, too had a dongsaeng who was autistic, but ried to live a normal life. he was the one who suggested to his family to let his brother walk to school alone to be able to be independent and as normal as he could be, Not knowing it would be his brother's autism and his fear of being alone outside that would kill him. He was run by a truck, he was too late in crossing the streets.
Kim Do Han told this story to Cha Yoon Seo. As the story goes, I root for these two. The amazing chemistry, the atmosphere that surrounds them are awesome. While Park Si On is a cute dongsaeng to his noona Cha Yoon Seo. he is beginning to like her.:))