Based on what she'd learned from her husband since her return, he was the only one issuing the summonses those days. Few knew he had the capability. It was thought best that he keep that as secretive as possible. None of their enemies needed to know how far gone their master truly was. Convinced that it was just Antonin seeking to get her immediate attention, Hermione didn't feel any less worried about the random summons. What was so important that he couldn't just send her an owl or wait until she got home? The end of the day was near. She would've been home soon. Such a dramatic gesture wasn't necessary.