That part, jumping bail by walking into an embassy, isn't all that unusual. China is worried enough about it that they sometimes shadow politically sensitive detainees who're out on bail to make sure they don't get close to any western embassies in Beijing.
I assume that would be a common trigger! Until that point, they may hope to be acquitted and not have to flee the country. For example, Chen Guangcheng escaped house arrest and fled to the U.S. embassy. The Chinese were not happy about that, and applied pressure, but they didn't send police into the embassy.
