The man of prophecy can't be the guy who knows all the steps and goes through the motions of following them because he wants whatever power "being him" will confer, it's gonna be the guy who stumbles ass-backwards into fulfilling every condition while freely pursuing some other bullshit of his own, without ever knowing there was a prophecy. Knowing too much about the destination can ruin the whole journey.
Like hypothetically if we assume a major prison break is on the checklist, we could also fairly assume Blackbeard went to Impel Down because he knew about that part. He formulated his plan well in advance and only broke out those who were on his recruitment list and agreed to throw in, it was a calculated play. Meanwhile Luffy jumped in headfirst on no notice and with no plan beyond "save Ace", and managed to take like half the prison out with him. Would be very surprised if Rocks and Roger didn't have a similar thing going on.