Indeed. North Korea is playing its cards right, considering how limited its hand is. With the new UN sanctions, they are basically trying to build up such a threat, that the others will eventually budge and lessen the sanctions.
And it makes sense for them to try, because it has worked every time in the past. Effectively, their aggressive behaviour is purely a bargaining position. Although, as the US Defence Secretary correctly stated, 'you only have to be wrong once'. And that is exactly the mentality North Korea is counting on we are feeling.
The most likely break out of war in Korea would be if South Korea either wanted it or provoked North Korea deliberately. Because even North Korea knows it cannot win against South Korean and the US.