Possibly both packs turned off by mistake, cabin altitude alert warning followed by mask deployment and emergency descent. Error realised, packs turned back on, cabin pressurises and flight continues.
Non ETOPS so no 2 engine depressurised figures figures in the flight plan. A climb back to normal cruising altitude should only be considered if fuel critical, no diversion airport available and the cause of the pressurisation failure was a crew error not a system problem.
In some areas of China the terrain is so high that additional passenger oxygen has to be carried on certain routes as a descent to 10 000' may not be possible.
If a suitable airport was available a diversion would be the preferred option. Emergency descents often leave passengers requiring medical attention.