A medium humanoid (John), adjacent to no other characters, attempts to overrun a medium humanoid (Bill) who has Improved Unarmed Strike, Combat Reflexes (with three AoO) and Stand Still, and continue his movement through and out of Bill's adjacent squares. What happens?
Is it this: John moves into a space adjacent to Bill, provokes an AoO as part of his overrun maneuver. Bill takes his AoO as an unarmed strike (he can't use stand still because the AoO is not provoked from moving through adjacent squares) subtracting any damage from John's roll to overrun. John succeeds on his overrun roll and moves into Bill's space (does this provoke an AoO?), then moves from Bill's space into another adjacent space (does this provoke?), then moves from a space adjacent to Bill into a space not adjacent (does this provoke?)and proceeds to his full move.
When does the Stand Still take effect?
Additionally, what happens if John has improved overrun?