North Korea warns foreign diplomats
Of course, fleeing is no option because then the North Korea's government is free to do whatever they like. But a leader who gives such a warning should never be trusted. Indeed, one can only conclude the leader may not be very well in his head.
The USA understands this and already stopped a scheduled military exercise with South Korea to prevent tensions will further increase. This is a good step although one has to be careful that North Korea will not interpret it as a sign of weakness.
Maybe governments should speak more directly with the North Koreans leaders as they don't want to be ignored but be taken seriously. Maybe senior diplomats, send by President Obama, the Chinese President Xi Jinping, the Russian President Putin and the South Korean President Park Geun-hye (all major players involved), together with large amounts of journalists and camera crew may lessen tensions as the regime may see it as an acknowledgement. But probably this too will only work temporarily because then the regime may start thinking that even more military might may further increase his powers.
And thus maybe we should ask China to talk to the North Korean leader, so they can say in polite manners that he should dampen his rhetoric. As we now already know, the tougher we are with North Korea, the more extreme the regime and thus probably being polite will be the best way unless of course that doesn't work. Still, as China often supported that country that is feared by almost any other country because of its unreliability, they now start fearing it as it is getting out of control.
Maybe we may have to solve the problem one day permanently. But that of course is only possible when all powers involved agree as otherwise the consequences may be even larger.