The rules seem clear to me that you have only 2 options, 1. Stay and battle the Jap destroyer or 2. Leave the hostile sea zone and cannot move into another hostile sea zone. Right? The other 2 rules in the rulebook are for troop transports correct?
As @Wittmann said. There are no “Transport-only” rules included in the “Sea Units Starting in Hostile Se Zones”-rules. Of course the transport is the only unit allowed to load, but the movement itself is allowed to every sea unit. In general it is the nature of a Combat Move to end in a hostile seazone to conduct combat there. The “Sea Units Starting in Hostile Sea Zones”-rules is a specification and somehow extension.