Information taken straight from Rampidzier's guide on gamefaqs,
Requirements: Complete the mission "Keiji's Real Request" on 46F.
Location: Dropped by Keiji Maeda when you defeat him on the fifth floor.
I tried my best to explain how to get this mission to appear in the video, but if you're still having trouble then just say so in the comments section and I'll try to write a method for it here.
![](https://s2.save4k.ru/pic/RibTLSPV_58/mqdefault.jpg)