I don't see how you could possibly think that China would fail at restoring order in HK. China is different yes, but they still put bullets in the backs of people's heads with regularity. China doesn't keep official capital punishment numbers, but it's estimated that they kill more than the rest of the world combined.
I have no illusions that if China decides to put the smackdown on HK, and it's unarmed populace, it will swift, bloody, and successful.
I read something, somewhere (wow that sounds silly), where it was surmised that Gandhi's tactics only worked because it was against the British.
Had he tried the same thing against.. say the Nazis, results would have been much different.