What? How? China isn't going to just become a spectator on that possible conflict because N.Korea is literally right next door!! Besides, if any of the current leadership in China is just going to allow the slaughter and mayhem to happen against it's ONLY DEFENSE TREATY country, then China is going to be surrounded from all sides.
I am not sure I consider that to be much of a concern.
The reason why is that China is always surrounded by all sides.
But the geography was natural boundaries. The steeps to the north, the ocean to the east, the jungles to the south, and the mountains for the journey to west.
Was not easy to get into China. It always came from the north, but that was eventually taken care of. Then in the Age of Imperialism it came from the sea, but that probably is impossible today.
Only real threat now in terms of foreigners causing havoc inside China is infiltration from the western borders, of radicalism.
The good news is that all these anti-terrorism efforts on the part of China, and the regular discussions with the other members of the SCO groupings which includes the stan countries on the western borders, seems like the governments in the SCO have it under control.
A terrorist attack, still has to be planned. Hard to say right now, other than Israel doing the assassinations, and Indians killing people in Canada, which are essentially terrorist attacks, really not sure which states are still involved with this doing it on a regular basis.
Sure, the Americans could be paying off a terrorist to do something. But after those towers fell in New York, they probably got a clue now.