Now, it's obvious that Zoro was going to fight Kaido, yes. But I don't blame those who doubted it. Theres no historical precedence for Zoro going to "the roof" before(it hasn't always been a roof, but you know what I mean.) And for some reason, he spent way too much time just lollygagging around the first floor. I get that, plotwise, Marco was always meant to take him up, but it certainly felt odd that he didn't seem to have any sort of plan while Luffy, Jinbei and Sanji, as well as Kidd and Killer, were steadily progressing