Meanwhile, the Chinese PLA certainly doesn't suffer from any manpower shortages to contain the situation when they eventually want to.
You don't need guns. Making car bombs and IEDs requires only determination and some practice. PLA as any modern army is poorly equiped to combat urban guerilla. Such a dense maze like Hong-Kong had never been experienced by any army.
Loss of face for China would be collosal if any sort of prolonged and effective resistance happend after intervention.
But I hope it won't be necessary.
I doubt China ultimately cares about loss of face.
In a population of 8 milion you will find more then enough smart, determined, intelligent people who can learn quickly enough and innovate.
The only thing that China is afraid of is the loss of face :-)