First of all, I would like to say that it is very interesting that North Korea and South Korea have opened fire at sea. According to BBC News, a North Korean ship crossed the "line" and was shot at by South Korea.
This is not the first time such an event has occured. However, it is important to note that these such disputes and "bullet trade" makes this conflict alarming to the extreme. Beyond that, the delegate of the United States wants to emphasize the necessity of a resolution NOW, trying to solve the problems between both nations and furthermore dismantling North Korea's nuclear weapons program. If South Korea and North Korea go to war, there is a risk of a nuclear weapon being launched by North Korea. The United States and the world cannot bear that threat.
Now, if I'm not mistaken, North Korea's resolution involves the establishment of a nuclear energy program in North Korea, financed and supported by the United States. Now, the delegate is willing to agree with that, but ONLY in the case of a dismantling of North Korea's nuclear program. And furthermore, it has to be monitored (or done) by the United States. We cannot bear taking risks.
Now, delegate of North Korea: such a non-compliance to a resolution passed by the Security Council will motivate nations to effectuate disciplinary action from the United Nations. Best case scenario, sanctions.
The delegate of the United States agrees with the delegate of South Korea, removal of troops cannot be given before the dismantling of the nuclear program. Only after, or at the same time.
Lastly, the delegate would like to remind the delegates of what happened during World War I - the entirety of the European continent was at the brink of war. The alliances, the militarism, the colonialism, among others, was dividing Europe and tensions were escalating. All World War I needed to happen was something such as an assassination in Bosnia to eclode. Similarly, today tensions between N. Korea and S. Korea are heightened enough that one day something (such as the clash of two vessels, maybe) might clause these tensions to eclode into war. This is what makes the need of a resolution NOW so great - there should NOT be ANOTHER war in the Korean peninsula.