Turn Option: Change Zone
The combatant may move from their current zone into another, representing a shift in focus on the battlefield.
Moving into the Aggression Zone, however, is a free action. It doesn't take up a turn. This being the case, you can move into or out of the Aggression Zone and take your turn as usual in the same moment.
Movement into or out of the Aggression Zone must be done before a turn's action is taken. Therefore, for example, a combatant cannot attack from within the Aggression Zone and then move out of it. They must first move out of it and only then can they take their turn as normal.
A combatant who moves into the Aggression Zone must stay there for the duration of the turn in which they did so.