It's not really frozen so much as it is a matter of method. When we take you, you are from a specific point in time. We get you here without any fuss because, surprise, we're not the bad guys.

Theoretically, anyone with access to other worlds could bring something in, but as we doubt any of them would put forth the personal effort to bring it here the way we bring you here, it's complicated and takes time and is generally a pain in everyone's royal behinds. To pull something like that would honestly be a ridiculous undertaking.

But it's possible. That or someone took a peek into your little pocket of woe and copied what they saw. All in good fun for them.