I don't really have much to say about this, to be completely honest. It gave more mystery to some existing unknowns and it was a nice change of pace from the previous three chapters. Ooishi and the MC really shine here, but as much as I like this chapter, giving it a 9/10 would be unfair to the other three, as this one really shows it's a bonus chapter at times (plus it's quite short compared to the rest). Still worth it and a great time regardless.