Katherine is in the main bar area buying books, computers, construction equipment, food, and other such things and getting them out the door as fast as possible.
...They don't want the imperial government in control of the door. They could be a lot worse, but they're paranoid and authoritarian and might be a disaster. When they get a radio call from a lookout that someone is approaching New Dover at speed, Katherine tells everybody that it's all in Har who's going to Har.
No other visitors have come in yet. She shuts the door relaxes a bit from the fast-paced ordeal that was that big evacuation - and it's not even over yet, they have to build homes for everyone on the other side. She would like to wait here for years and years, looking for someone who agrees with her and could bully the Imperial Government into figuring out something else to do with all the slaves - but she'd get old, and so very bored, too.
She unwinds for one last day. Nimo and Valanda have all the time they could want in Milliways, and then she exits too and lets the door close behind her. At this rate, she's probably going to see Milliways again eventually, anyway.