ND,
I can't chime in on 'active' military service but I've been a civilian employee of the US Army for over 30 years. I decided long ago that I could best serve by working to provide our soldiers with the best possible equipment possible. It has been a rewarding experience to see in use some of the equipment that I've helped develop.
One thing to consider is to combine your 2 passions by working fire fighting or EMT for the Army. You could get the best of both worlds.
Tom