Carl and most all of the other POWs are noted to be naval aviators but when discussing the group, the term "soldier/s" is used several times. No naval personnel would refer to themselves as soldiers, at any level.
No Vietnam War American prisoner was ever released to go home and surprise his family. Families were notified by the U.S. military first. They were then brought to an air base to meet the prisoner's plane.
There was no such thing as "early" release for North Vietnamese-held POWs, for the simple reason that there was no term of imprisonment. Other than occasionally for humanitarian reasons, American prisoners were held by the North Vietnamese until their release was negotiated in the Paris Peace Accords.
The army captain in the opening scene (assumed to be army as he was wearing the ribbon of the Army Commendation Medal) was wearing his ribbon bar the wrong way around.