What I saw in the sinking was a rogue Military General making a cry for help to the US for assistance in a coup (or at least acknowledgement that we knew that they wanted to take control of the government)
I pair it with MAO and Fidel original wanting a democracy and America being tone deaf.

Remember the lack of bravado before and after the sinking. Kim would have made this HIS personal victory. The order would have to come from Kim, yet he was involved with trains to china and appearances as well. Kim is a very "controlling guy".

Shortly after the sinking of the SKOR vessel, a very high ranking general was fired and a purge shortly followed. The regime is very weakened.
China has been bribing guards all along the border and yes, sending in modern technology so the people see what is going on in the rest of the world. The GULAG is about to end there.

Markets are to become legal again as such dire consequence the state their economy finds.

It has never been this bad in NORK. It has already collapsed IMHO.
The troops are getting edgy and the rice and grain sheds have been emptied to the population.
Last step is lash out.