The cases her judge deals with aren't this high level but .......
When a judge is not ready to make public ALL the information, or he/she feels the need to protect the rights of either the state or the defendant. He may have also done this to make sure all parties involved have their i dotted and their t's crossed. Example a legal document is presented and a typo exists, The judge knows, technically ,that this is incorrect he may call both parties to chambers where of course the side without the typo argues no more delay, the typo side says let us correct this first, you've had plenty of time the other side argues, The judge will then settle the matter citing case law that supports his decision to delay or proceed. I'm not saying this is what happened cause I don't know.
This is just an example that was given to me of why a judge sometimes has a chambers type hearing.