The mitsvah was completed, he had made his 4 steps, he was ready to return but Rabbi Shimon (butler/driver/hassid) refused and said; now that we are here we will visit the holyland. Rabbi Nachman would never insist, so he pleased his driver, but when Rabbi Nachman tried to go to Jerusalem he was accused of being a French spy and was not allowed to travel there.
This "small event" in the life of the Tzaddikk was a terrible disaster for humanity!
Napoleon I (Bonaparte) had been victorious so far and was about to conquer Jerusalem, he was in Akko! His speech, that the French Nation would give Jerusalem over to the Jews as a present was written and ready (he was hoping this would stop anti-semitism in Europe and give Jews a place of refuge).
There is a story of Rabbi Nachman where a man with a stick shoots at a wolf, hears a bang and the wolf drops dead, because the real hunter with the gun shot it at that very moment. This is what was happening here. Rabbi Nachman makes his four steps and conquers the holy land letting Napoleon believe he did it.
BUT.... Rabbi Shimon, D I S S O B E Y S. Similarly Moses tells the nation after the event of the spies NOT to attack the King of Arad, or they will be wiped out. They DISSOBEY THE TZADDIK and get wiped out. 40 years later in the same PLACE, the nation is attacked by the King of Arad, who takes captives. The reason the King of Arad had the power to do this is that the nation of Israel had sinned here previously and the "place" took on this bad trait weakening Am Israel. In the same way, one shouldn't sit in the PLACE of scoffers, even when the scoffers are gone, because the place is condusive to evil speech.
If Rabbi Nachman had taken his four steps and he and Rabbi Shimon had gone home- the land of Israel would have been conquered for Israel by France (Ephraim ?). If the Tzaddik wants something, better execute, the whole world depends on his slightest moves.