China should start evacuation drills first with a some college students over the summer holidays in order to discover what preparations are needed to do the evacuations and to keep people out of cities for long enough time. These drills should be progressively enlarged. The real evacuations must be started days before missiles actually fly.
In cities, those too young to go to vacant villages, expectant mothers, etc should be give priority to shelter facilities like MTR stations. The old, who don't have too long to live, will have to take their chances by themselves...
China must act to give the young, and those who have critical knowledge to pass on, the best chance of surviving a full scale nuke war.