I get the impression from this translation that WB had the OPe Ope no Mi within his crew before Doffy started looking for it. It sounds like Kaidou and WB have a history and it sounded like Kaidou was blaming WB for not being able to die. Maybe Kaidou kept pestering WB to be killed by him and WB got annoyed and said you know what now you can't die.
That or Kaidou was insinuating WB was the only one able to push him close to death which seems to be what he wants. I'm not sure, will need to wait for MS probably but this translation did give that impression at least to me.