Some people think SeungYoo was abused while he was at the MIT, but at the beginning of the first episode he said that he went to visit someone for their death anniversary. What if the sudden death of this important person made him run away from MIT? Or, what if he believes he caused the person's death? So he feels guilty, especially while studying math, since they both studied together. Regarding the relationship between SeungYoo and the teacher Yoon Soo, well it's soon to tell what will happen. Maybe even after 4 years they won't develop feeling for each other, apart from admiration and respect as fellow mathematicians. (Or at least this is what I'm hoping for, since a 15 year gap is big when someone is in his 20s and someone in his 30s).
Regarding the relationship between SeungYoo and the teacher Yoon Soo, well it's soon to tell what will happen. Maybe even after 4 years they won't develop feeling for each other, apart from admiration and respect as fellow mathematicians. (Or at least this is what I'm hoping for, since a 15 year gap is big when someone is in his 20s and someone in his 30s).