I'm making some assumptions here, but the N. Vietnamese viewed the prisoners as political negotiating chips. They were very casually indifferent to their surviv

I'm making some assumptions here, but the N. Vietnamese viewed the prisoners as political negotiating chips. They were very casually indifferent to their survival and indeed many died. Quite a few were killed. However, the N. Vietnamese tried to paint a very different picture publicly, that the POWs were being humanely treated. Doug openly accusing the N. Vietnamese of murdering Stratton meant the Stratton's value to come out of his imprisonment alive was greatly increased, as that made the N. Vietnamese look good and the Americans look more foolish. Stratton, for various reasons, may also have thought the N. Vietnamese would kill/disappear him because he had signs of obvious torture, which would put lie to their claims of humane treatment. The fact this happened "in Paris" indicates it happened during the Paris peace accords (which effectively ended most US involvement in the Vietnam war), so was a matter of concern to the top officials in the country.