Thanks for the chapter!
Gotta love politics, unnecessarily complicates and makes a mess of everything. It's nice that Celestia wanted to help Richard and wasn't the head honcho, but should've said something to Grey a hell of a lot sooner rather than this crazy plan to help Richard. If he had stabbed her that psychopathic, selfish glasses guy likely would've gunned him down so his achievement would be award posthumously. Would like her to live so can be with Richard and walk along his path for atonement as well. Granted as she said she did a lot of bad things but she was a victim of Dhala's warped conspiracies as well so should be tried and judged rather then let die. That and the anti-Queen faction would use her death as an excuse to close the case to avoid any investigations from learning of their involvements or anything they're trying to hide.
Personally I bet that doctor is the leader known as Hecate and has been using Celestia as a figurehead. Someone knew or learned enough about the fortress' legacies to know how to use and activate them so while Celestia wouldn't have enough time or cognitive facilities to have done it between her work as Student Council President, running the parties, and getting smashed on Mermaid's Blood herself (which she mentions weakens the mind,) while the doctor knew the location and how to activate the legacy for safe room she 'hid' the princesses in, had free time to investigate and learn about the legacies, and wasn't addicted to Mermaid's Blood despite holding a great position to cover up or discover students taking it along with being an ideal distributor once turned. Also, at the beginning it was mentioned that some students had been taking it thinking it was a safe drug. Students wouldn't trust Celestia offering the drugs to them, but would as prescriptions from the doctor who would have ways of smuggling the drug in with real medicine. Besides, what competent doctor wouldn't notice or mention students showing abnormalities such as increased blood rate, dilating of pupils, gaps in memory, sudden increases in performance, and other signs? Mainly she's too composed and rational as a school doctor who should have no battle experience and hasn't mentioned any feelings of guilt or responsibility for not noticing a student under her care was taking drugs before dying much less any action to ensure others weren't as well but was acting like everything was normal. As Dr. House said, if someone doesn't react to an obvious issue it's because they're trying to avoid attracting attention to themselves, (for him it was his patient's wife not saying anything about patient being orange because she was hiding fact was having an affair.)
