He'd raw dog his way through the scabbards with ease, the beast pirates wouldn't even try to stop him but Sakazuki's aboslute justice will still cook them
Luffy will jump the frame straight away because he knows the most besides Jinbei how lethal Sakazuki would be, Hell I can see Jinbei and Luffy trying to jump Akainu and stalling him
Luffy either makes it before or after the scabbards are down on the ground with lava flowing on their body and condition being unconscious
Now here's the thing about shanks, his CoC would probably warn Akainu but that wouldn't stop him and I have a hard believing that the red hair pirates will show up in front of Luffy
Akainu is deadly as hell, the best bet the SH (Jinebi, Sanji, Zoro, Luffy) can do in that scenario would be to try and drive Akainu away as his AoE is also very potent, and they'd need the amount of Haki to do so
however I don't believe Sakazuki would be too blood lusted to where he's accepting a difficult match-up
So the SH would probably drive Sakazuki away before they all get gassed, Akainu is on the caliber of Kaido, Whitebeard, Shanks
the thing about this is as that Akainu isn't greenbull and the scabbards would be made easy work, Luffy and the gang was already observing Greenbull vs Scabbards/Yamato
with Akainu I have no doubts they'd jump in as soon as possible, especially Luffy and Jinbei