This scenario does not include any destroyers for either side:
I attacked two Japanese Sea Zones. The sea zones were next to one another with one in front of the other. A lone submarine supported by air planes moved through the first enemy occupied sea zone to attack the sea zone behind it and adjacent to it. Other units attacked the front sea zone. The front sea zone battle ended with all enemy units destroyed. The back sea zone battle ended when I decided to retreat my sub and supporting planes.
The question is can the sub retreat or is it stuck in the sea zone where the battle occurred?
From what I read in the rule book (Pacific 1940, Second Edition, page 20, Condition B) it cannot retreat the way it came because the sea zone was not friendly at the beginning of the turn. This indicates that the sub must remain in the sea zone where the battle occurred and has no retreat option (except submerging which does not accomplish the goal of saving the sub from counter attack).
Thanks to all who respond!