The US has its nukes on everyone's borders, floats its ships through their waters, flies through their airspace. This is not an escalation. Allied nations send vessels through one another's ports all the time. Russia does this regularly. This moment is intense so it is getting attention and there is a case for not doing it, but it is not escalation. Keep in mind the DPRK has had submarines go to Cuba in the past 20 years.
On the bright side, it is heartening to see Iwata's influence and decency still influencing devs today