He cannot be so sure as to what exactly is running inside Akainu's head, no, there's no way anyone could know about such a thing, at best, Nicholas could only guess. The old geezer should know any better, he was there, Portgas D. Ace died in his own hands, and it set lose all kinds dark things into the world. But Ace is Ace, and Kaido is a Yonkou. There's a difference.
Pirates are such delicate creatures that they will instantly lose their heads on a slight insult given to them. And there was enough insult in executing Ace and then killing Whitebeard at the same time that could easily throw any pirate on the edge. The act has definitely done the Marines no good, if anything, it only made things worst. Those people above knew that. The wound created by that event 10 years ago hasnt fully healed. That much was evident. And executing Kaido publicly will be like picking on the scab, reopening the wound, and then putting salt into it. Perhaps, may be that is what Akainu wants.
Nicholas mind drifted further into deep thought, hoping he could find some sensible reasons for all of this things. But he didnt find any. He could sense Tamaki looking at him intently, may be figuring out what could be running into Nicholas' mind. The younger man hasnt said anything for awhile, and so does Nicholas. They just stood there at starboard, staring at the vast blue sea.
Fortunately, the two Commodores in his ship has showed up just as when Nicholas thought he couldnt bare the silence anymore. He has almost forgotten about them, they were suppose to be hitching a ride to Baelthymer. Nicholas figured he's going to need to explain to them that the plan has changed if he wanted to keep the order in his ship, and soon.
Nicholas cast away his grim expression, and then put on his usual cheery self. He greeted them both with a big smile, "Hajime-kun, Drake-kun, how was your sleep? I am aware that the rooms I have given you was not adequate to your status, and I do apologize. You came in such a short notice I only had the Captain's and the Vice Captain's rooms at my disposal, but I should think they are comfortable enough, no?"
He can feel Tamaki tensed up to this, he was not very happy giving up his own room only to be thrown into the common area to sleep with the rest of the crew. But Rogelio, his ship's captain, was an exception though, he seem to have found a comfortable place in the crows nest and has been living there for the better part of the trip without complain.
Tamaki leaned on towards Nicholas left ear, and then whisphered, "Should we tell them the situation?"
Nicholas nodded, he needs to tell them about it anyway. "Apparently, we have a change on plans." The Rear Admiral announced, "A News Coo just arrived this morning bearing a letter from Base G-5. They're summoning us for Kaido's execution. The old man wanted every Marine officers to be there. They suspect a pirate attack might occur during the execution - which may very well be if you ask me. We're heading back to Mariejois as we speak."