Why did Commander Jameson move up Day's execution? Why wasn't June notified?

From the text:

“Commander Jameson suggested it, and she got the courts to approve it. I think she’s still pretty mad about how hard Day bit her hand when he tried to escape.”

But that’s not all. Commander Jameson chose not to tell me about this. If Thomas already knew last night, that means she told him yesterday evening, at the latest, before sending him home. Why wouldn’t she tell me? She should think I’d be glad to hear that Day is to die twenty-five hours earlier than planned. Unless she suspects something. Perhaps she wanted to throw me off just to test my reaction.