@Redshirt Army
Modified vote in order to take your points into account.
[X] Use grief to communicate with Mami, have her call for Homura to timestop
now. Give Rionna
no time outside of the privacy field to send commands to her shades.
-[X] While doing this, continue speaking to Rionna so as to distract her from what you're doing. Get her attention focused
entirely on you.
[X] Once in timestop, explain shade hazard then create a griefhax soul viewing effect (like the one used to observe Oriko's soul), and use it to avoid any lingering shades, then bring in Sayaka. Explain what you've learned about Rionna to them. You're not going to let that stand.
-[X] Explain plan to team, ask for input and advice.
--[X] Plan: Have Sayaka or Kirika enchant an antimagic box that suppresses Rionna's magic (and not our group's). Timestop degem Rionna
immediately into the box. Have Sayaka try to copy Rionna's magic, so that we can try to put the shades to rest, and have access to someone who can diagnose soul maladies on hand. Keep Rionna's body stored in Homura's shield or our hammerspace for the foreseeable future, until we've got enough other girls working with us, and
stability, to try to rehabilitate her.
[X] If anything goes wrong during this plan, and Rionna looks to become combat capable again, immediately degem with all needed force.