You misunderstand the scene.
The reason Oda had Luffy asked Zoro if he needs help was to show how careless and naive Luffy still is and he still has room to grow as a fighter. There's two parts to it.
1 - This seen is similar to happened on the rooftop when Luffy wasn't paying attention and needed Zoro to save him from BM. Zoro reminding Luffy to stay focused on his opponent. Luffy lostvfocus on Kizaru was played. Kizaru goal is to take out Dr. Vegapunk. While Luffy was fighting clones, Kizaru got close to Dr. Vegapunk.
2 - Zoro took Luffy not to trust Lucci and he was right. Now Zoro has to clean up Luffy's mess and Luffy wants to help because he realized he was wrong.