The cats were playing a bit rough and Hera was tired of it, so she called a Time Out on herself. The little cage is where bad kitties are put for a designated number of minutes when they're getting into things they shouldn't. Lightning has spent enough time there that all we have to say to him is "Do you want to go to Time Out?" and he'll usually stop what he's doing.
Hera knows this. She went into the Time Out cage, and Lightning wouldn't come in after her. He'd stand in the doorway and bat at her, but all she had to do was shrug backwards, and he wouldn't follow her inside. So she sat there, like a kid playing Tag who was "on base," and glared at him, as he ran around the room.
Then she came out and jumped him when she was good and ready. Ah, cats.
Hera taking a break from Lightning