With respect to antiaircraft execution, I believe it is a message. To the outside: "we are dangerous". So too the tests.

How can one maintain power if dead?

I do not think Kim believes he can survive the true anger of the US.

I think Kim can only win the peace, and he knows this.

Otherwise, what is he waiting for?

Semper Vigilantes, Numquam Exspectantes

Always Watching, Never Waiting