I'm not sure about actual war related deaths of Titanic survivors, but there are plenty of connections - Edmond Navratil fought with the French army and was a prisoner of war. Dorothy Gibson was arrested by the Gestapo. Jack Thayer committed suicide after his son died fighting in WWII. Charles Lightoller used his personal boat to assist with the evacuation of Dunkirk in 1940. I'm sure there's many more examples....hope that helps a little.