I'm not seeing how that is a contradiction. His full sentence: "Eventually, I was able to get myself away from this world while serving in the United States Nav

I'm not seeing how that is a contradiction. His full sentence: "Eventually, I was able to get myself away from this world while serving in the United States Navy." I interpret "while serving in" to mean that the process overlapped with his time in the Navy. If there was no overlap, to me it would have been more natural to say something like "upon joining" or "by joining" instead.