A while ago, I wrote that one of the important themes of this arc is the use of strategical advances. This chapter is a pretty good summary of what I meant:
With Vegapunk about to reveal what (partly) happened in the void century and the SHPs about to flee, the Gorosei need to prioritise their goals. In this specific situation it means that the elders do not focus much on the SHPs and their flight, but are much more concerned about what Vegapunk wants to reveal.
This in return gives the SHPs more room to flee, because the Gorosei are occupied with finding the right transponder snail and stopping the transmission. The fact that the first snail up in Punk Records (the one that Mars destroyed) ended up being fake, makes it clear that this snail was a mere diversion. Someone from the SHP’s side had put it there to occupy the enemy. This gives the SHPs more time to escape and also hinders the Gorosei to really engage in a fight with our protagonists. Because for the Gorosei it is more important to stop the message from Vegapunk, rather than fighting Brook, Chopper, etc.. This is why Saturn rushes past Nami and co. in search of the transponder snail. It means that for the moment the SHPs are safe.
It is rather odd, for the SHPs to come up with something of this strategical magnitude. It just means that in the background of all, there must be someone with a strategical proficiency, who had evaluated what would make the Gorosei divert their attention away from the SHP’s flight. And with setting up the fake snail, he has made it especially hard for the WG to stop the transmission and gave the SHPs time to flee the island.
Now that Oda has ended the fight between Zoro and Lucci, Zoro is now almost with the others again, with Brook already calling out to them to hurry up (meaning they are in sight).
I would like to note that this fight did serve no purpose for Zoro. It did not slow the SHPs down as they already had to wait for Edison to expand the clouds. It did not make Zoro and Jinbe delay their arrival to bring some tension into the encounter with Saturn. It served nothing of this sort.
And if it didn’t serve a purpose for Zoro and Jinbe, then it must serve a purpose for Lucci as the only other participant of the fight, who is still able to partake in the plot, since he didn’t go down. The fight made Lucci on one side able to separate himself from the group again and able to act independent now. He can do what he wants with the SHP seeing him now as an enemy. This means that the fight was not a means to stall Zoro, but to stall Lucci and for him to be able to separate from everyone.
I also want to remind you of the words, Lucci said in his fight with Zoro regarding the behaviour of the SHPs: "Those fools will never make it if they can't cut of the arm to save the body!!" - and exactly this is why Lucci wants to be seen by everyone as the enemy again - he wants to help them escape. And he knows that for this, he has to stay back. But the SHPs would never leave an ally behind, if they knew he was to die or get seriously in trouble. So, Lucci needed to be seen as evil again. Now, he can easily act, if – for example – someone would not press the button to shut down the Dome (Stussy) or if a strong enemy was to go after the Sunny on her flight to safety (Kizaru). Both Kizaru and Stussy need to be stopped and Lucci knows this and will act upon this need.