This story is in Mission 4-1. The third chapter is all about Hibari in Hebijou's school and Hanzou's rescue with the last key mission being Asuka's infiltration and grabbing Hibari.
OK I was thinking more at the end of chapter 3 So its just at the start of 4. So after Yagyuu's attack on hebi. Knew it was some where around there. with burst its hard to tell because it does not go to the story any more you can just skip it.