Regardless of all the scene swaps, the basic chronology holds:
1) Spock deposits his katra, with instructions to take it to Vulcan.
2) McCoy goes crazy and cannot act on his inner voices to accomplish #1; he only gets his friends confused.
3) Sarek rushes in, accusing Kirk of deliberately refusing to hand over Spock's katra, while also stating that Spock's body can just as well rot on Genesis.
4) Kirk figures out the katra actually went to McCoy.
5) Sarek recognizes McCoy's distress and says Kirk must bring "both" to Mount Seleya for relief.
6) Kirk royally misunderstands and thinks he has to bring the dead corpse, too!
7) Meanwhile, McCoy is arrested on charges of wanting to go to Genesis.
8) After Kirk has already launched into his plan to get to Genesis, events on that planet establish the correctness of the approach after all.
The only question goes, does Kirk misunderstand out of basic stupidity, or does he deliberately take Sarek literally because he has already been musing about this "life from death" thing? Clearly, Sarek himself is still unprepared for the idea of resurrecting his son when the heroes bring the walking corpse to him... But Kirk is better versed on Genesis than Sarek is. And while he may not be up to the minutiae of Vulcan mystiscism, Spock/McCoy at one point goes from wanting to go to Vulcan to wanting to go to Genesis - Kirk may well have heard some of his rantings from after the moment when he makes the transition from one Promised Land to another.
Timo Saloniemi