I must admit, I did wonder about that? Actually, according to the plot he's a naval officer. So when he talks about being in the field, he possibly means onboard ship, unless he's a Navy Seal? But he also suggests he's used to roughing it in the field, which doesn't seem to be talking about being onboard a ship. Because I reckon modern US warships do have reasonable facilities for the crew. It's not like they're living in tents, having to cook their food over fires and shitting in the bushes? I suppose if he's a senior officer in the US Navy, he could still be active in his 50s.
Perhaps though, the Dev forgot that he initially said that he was in the Navy? And he's since morphed into an army officer? If that's the case, and he's leading his men in the field, which would probably mean recently serving in Afghanistan. Then yeah, being fit and healthy at his age, would still be a necessity.
