The first part of Nja himself's spoiler summary.
Explanation of how Luffy and co came flying.
Their ship was caught in the sudden high wave (caused by the earthquake fruit)
Then the wave froze, and they were stuck in the ice.
Then Luffy heard the Marine's plan to execute Ace early on the communications,
so they started rampaging to try and get out of the ice quickly.
The ice broke, and their ship came falling down.
Jinbei rescues the devil fruit users that fell into the sea
Luffy: Ace!! I came here to save you!
Croc takes the initiative to attack Whitebeard with his hook, saying it's been a long time Whitebeard
But Luffy, still wet, stops him
Croc: What do you stop me? At the point we got out, our alliance is over.
Luffy: That's Whitebeartd isn't it? Ace likes him, I won't let you.
Everyone's eyes are set on Luffy, and comments one by one (The Admirals, Shichibukai, Smoker, etc)
Whitebeard: You came to rescue your brother eh? That strawhat... that was Red Hair's
(He remembers about Shanks, and asking who took his missing left arm and such)
Luffy: I know you want to be the pirate king... but I'm going to be the pirate king!
Whitebeard: Damn cocky bastard... just don't get in our way!
Luffy: I'll save Ace the way I feel like!
Ivankov and Buggy looked shocked at Luffy talking to Whitebeard on equal level
Kizaru: Can we execute all of them?
Sengoku: Of course.