You all were just told that you have to kill each others if you want to leave the academy. So, naturally, after that, everyone scattered around the first floor, which is the only floor currently accessible, just to be away from each other. Byakuya is no exception as he silently sit in the dining hall, reading with an empty cup next to him as he had most likely been drinking coffee. Until you approach him. Since it's a free time, you decided to try and spend a bit of time with him despite how unapprochable he seems.