@dafater: "Ruka, who will want to know ytf he wasn't at work."
Author told us he's going to blow off work.
Given the lack of Ruka appearing in this chapter to ask him why he's skipping work, it's a safe bet he was too afraid to tell them ahead of time and called out sick just before work.
What do you think Ruka's response will be to hearing he skipped work because he was sick?