The Party controls the Army and the Army has all the guns. The Party has greater surveillance and control of civilians than the Nazi Party ever dreamed of having. But the Gestapo had the whole nation under its thumb.
I don’t see where China has any reason to disintegrate, although it may have some turmoil around succession if Xi is forced from office.
[The Party controls the Army and the Army has all the guns.]
Neither the Party nor the Army are monolithic. Each member will parrot the political line of the moment, but looks to his own personal advancement. (Think of how Yeltsin, a member of the Soviet nomenklatura, came to power. Ideology is just a veneer for individual struggles over personal power and prestige). Regicides are fairly common throughout Chinese history, many perpetrated by powerful courtiers close to the throne. The First Emperor’s heir was killed by his closest advisor, Chief Eunuch Zhao Gao.
https://en.wikipedia.org/wiki/Zhao_Gao#Coup_following_Qin_Shi_Huang’s_death Deng Xiaoping came to power via a coup, at the expense of Mao Zedong’s hand-picked successor.
https://en.wikipedia.org/wiki/Hua_Guofeng#Ousting_and_death