But for real, teacher catching Ruri at one of her low moments and offering her to isolate herself while pretending to "respect her choice" (while not mentioning any alternatives first) is kinda evil.
Might as well wait for a next trait to appear and offer to euthanize her. "Hey Ruri, I know this set of wings that just manifested had ripped your clothes with the whole class watching, and now you wonder how to live down the shame let alone fit into society, but what if I offer you a way out in form of this .40 cal magnum I conveniently had, the one loaded with anti-dragon explosive rounds (pure coincidence ha-ha, don't overthink it!) and let you end it all right here and right now? C'mon Ruri, clock is ticking, Ruri, just blink if you agree, Ruri, and we'll end it all - the pain, the suffering - just a flash and it will all be gone!"
Ruri is a teen, and teens are already overly sensitive and vulnerable, as an adult you have the responsibility to guide them and show the way to accept themselves and fit into society.