Can Flash target a unit that is already in base?
Yes, Flash can target a friendly unit that is already in base.355.9.a355.9.b355.10 Flash specifies base as the destination instead of asking you to choose one, so the different-location restriction for player-chosen destinations does not make a unit already in base an illegal target.002355.4355.4.a
When Flash resolves, the unit cannot move because it would not change from one board space to another.448.1