Umbridge did not crawl into a hole. She had a thick skin.
The members of R.B., on the other hand, did want to crawl into a hole, because they wanted to resume their previous activities.
But as Harry and the others had agonized over before, getting in and out of the Chamber of Secrets was far too much trouble. Besides, it only had one entrance and exit, which was both inconvenient and unsafe.
So they would still have to make a Portkey first.
Although Harry and Qiu had obtained the method for making Portkeys from Ravenclaw's inherited knowledge, understanding it was one thing, and making one was another.
Portkeys might all look shabby and unremarkable, but that was deliberate. Extremely special materials were processed with extremely special magic, then molded into that shape.
It was not simply a matter of putting Portkey magic on any old piece of junk.
If that were really the case, to take just one example, the old boot Portkey Harry and the others had used to attend the Quidditch World Cup would probably have been ruined long ago if it had been left out for another couple of days, given how often it rained in the United Kingdom.
Therefore, making a Portkey, from preparing the materials to the actual construction, then setting the destination and troubleshooting, was simply not something that could be completed in a month or so.
"There's probably no hope for this school year. Let's make it during the holidays and use it next term," Qiu said helplessly after learning how Portkeys were made.
The school was a mess.
It had been that way ever since term began, with countless troublemakers filling the Castle with foul smoke and chaos.
Apart from Umbridge, the other professors all ignored it. Umbridge wanted to