At the end of the last season Ginny is happy to leave Morgan alive when she could easily have killed him yet now she is obsessed with having him killed. No reason is given for this even though it's the main plot of this episode.
When Isaac is asking about Morgan's wound, he mentions he used to be a Corpsman in the Marines. Navy Corpsmen serve with the Marines, but they are still Navy.
Morgan finds an automatic and checked the magazine to find it empty, but, as the slide was not locked back, there could be one in the chamber.