No.12871830 ViewReplyOriginalReport
The Geass Canceller reminded Shirley not only who Lelouch is but also of what Charles took away meaning she knows Nunnally is Lelouch's sister, Rolo is a fake and that the Emperor mind-crushed everyone plus many other minor things.

Also, Charles is in his throne room so either he got all of Ashford (or was it just the Student Council?) to go to his throne room or he has some kind of geass transmitting device.