I'm just curious, as it does seem plausible, but I find it hard to believe that many soldiers would blow a friendly soldier's brains out because they just assume he'd rather not die in a field hospital. Hopefully not too specific a question to answer.
Semi related question, in the movie Memphis Belle, they debated dropping a crewman out with a parachute in the hope that he would receive medical attention soon yet be a POW instead of wait until they got back to England. Is this true?