It's a measure of something - the fact that Nobunaga is, in fact, trying to not act like he owns every piece of the ship as much as everything in his life to this point - that he knocks. And knocks. AND KNOCKS. Actually the patience is so low, he might as well just break the door open.

Composed. He is composed. Like ice. But angry ice. A stabby snowman of doom.

If he was more sensitive, he'd realize Arthur is probably not in a great state and could be just as worried, but Nobunaga's a little too angry and more in ACTION than methodically plot out long term solutions and slow processes right now.