So it's [page=1913] what I assumed from Monday's strip, there's a "hole" in the shield wall, and it opens up the entire civilized universe to mass casualty attacks by terrorists or bad state actors.
Obviously this needs to be patched ASAP, but why do you think that Hayami would leave important details about the attack behind?
I'm going to state for the record that my fan theory is that when Hayami killed Alyss [page=1393] it had a profound influence on her, and she broke off relations with her former employer. Since Hayami knew that she knew too much, she knew she would shortly be assassinated. She stored a backup copy as well as some information of the planned attack in her dollhouse, knowing that there was a pretty good chance that Diana's obsessive-compulsive "stone-overturning" would eventually find it.
This theory is somewhat opposed by what was said on page=1900
>Kimberly: She was, and she was nearly finished with a masterpiece when she had to leave on some contract job a couple of years ago.
This implies, but doesn't rule out that Hayami never visited her doll house after getting back from Oz. It's also possible that she knew that after Venus23 she would have been watched closely, and thus she uploaded a backup and other information remotely to prevent her former employers from finding the dollhouse.
That makes Diana's purchase a good idea. As I noted before, Alyss could likely have made a claim but it would likely go to arbitration, giving the baddies plenty of time to steal it.
Edit to add: Perhaps Hayami decided that if she was to be assassinated, then at that point she would decide to switch sides. The dollhouse acts as her "dead drop" and bargaining chip.
page=1901:
>Kimberly: Well, sometimes she'd make a joke about how building this 'péreilleux miniature' was killing her.
>Kimberly: We laughed, not expecting she'd end up getting murdered.