He wasnt supposed to. He is not going to be the PK. Its a massive W for him that Oda decided to put him at the rooftop. Think about it, it was easier for Oda to have a Luffy-Law-Kidd vs Kaido. But the pirate hunter is so great that Oda had to make it a 5vs2
Yeah, he hid behind Zoro and saved himself from the strongest attack in the series from two yonkos. Pretty easy to look good when someone else is doing the hard work for you