Genocide doesnt require direct killing. Forced sterilization and destruction of cultural identity is also genocide.

From Wikipedia:

"the destruction of a nation or of an ethnic group" by means such as "the disintegration of [its] political and social institutions, of [its] culture, language, national feelings, religion, and [its] economic existence".

And there is plenty of documented proof of that. To deny that is to deny your own ability to see, read and think.

If one of them tries to walk out, do they just let them?

Watched an interesting take from one of the Chinese politician or whatever they are called there.

He was blaming the US imperial forces causing turmoil in Afghanistan which leaked into the Chinese side and fumed some of the locals now wanting to split from China and wanting their own nation. Pollie said their leader is an american citizen. So I guess china has been detaining these people? Who knows.