Ione waits until much of the afternoon is up before she makes her move. If Ione tries something, even if she succeeds, Security might expect the exercise to be over after that. Her plan is a simple one, she is on the Nethysian punishment plan rather than even the lax one, and Ione doesn't want to blow other girls' chances at avoiding punishment by making it clear earlier that more than one girl might be a traitor.
By the time Ione's moment comes around, Asmodia doesn't seem to be around, so Ione carries out the plan on a morose Peranza instead. She uses Message instead of shouting, on reflection, that gives them even less time to try Hold Person on her.
Message to Peranza:
Brace yourself, and don't react to what I'm about to say, or do.
KELTHAM EVIL TORTURES PEOPLE CHELIAX IS LYING TO YOU ABADAR IS YOUR GOD DON'T ACCEPT ANY RESURRECTIONS UNTIL YOU MAKE IT TO AXIS AND TALK TO SOMEBODY