Zhou Yongkang was China's Interior Minister. You may have heard of the expression Interior Ministry troops. Basically, Zhou had an army of paramilitary police (1m People's Armed Police) at his disposal. However, to mobilize the key military leaders for a coup would have taken a lot more time just for horse-trading. Zhou's timid response indicates that he wasn't willing to go all the way, which was probably another reason why he was kept on in the Politburo Standing Committee (which comprise 9 of China's most powerful pols, including Xi Jinping, Wen Jiabao and Hu Jintao). Still, if gunfire had broken out, I suspect Zhou would have had no choice but to win or die trying.
It’s amazing how this news has not travelled much in southern China. My wife just came home from Xiamen, and her family knew nothing about any of this. No surprise though.
That makes this little altercation in Beijing even more serious, as the standoff was between the most senior Party leadership. It would be akin to having forces loyal to Harry Reid and Joe Biden having an armed confrontation in Georgetown.