Talk:Kara no Kyoukai Collaboration Event/@comment-59.189.10.138-20160305062349/@comment-556400-20160305062957

Underneath the event banner at the top of this page, there are links to Main Quest, Free Quest, and Mission List. If you go to Main Quest Room 404, we have listed there "Complete Mission 39 to unlock." The link takes you to the Mission List, and you can see Mission 39 is to defeat 15 Assassin Servant enemies.

At the bottom of the Mission List is a chart of which rooms contain what kinds of enemies for these specific kill missions. Anyway, use those pages as a reference to determine what you need to do to unlock each room.