So… a few thoughts. I live in HK (having semi-recently moved here from the Bay Area, right before this all flared up). First, there's a ton of misinformation out there. Few sources have entirely accurate information, but the best English-language resource I've found on the subject is the local paper South China Morning Post (scmp.com). They have pretty accurate and unbiased live reporting of the protests as it flares…
What do you think are the chances that the tanks roll in, all protestors are shot or arrested, marshal law is declared for a few months, and eventually Hong Kong becomes just another city in China without its own special governance or laws?
In the 1960s Singapore annoyed Malaysia so much they were essentially ejected from the federation against their will.
It was a major shock at the time, but decades later the two countries are still mostly amicable. I sincerely hope China would consider this route.