I want to be a firefighter but I also want to do Infantry?

If you really want firefighting/ rescue skills? The Navy is a better choice. Damage Control is a good rate for what your looking for. They have spots on ship & in naval air stations. Coast Guard is a better choice as well. Trust me, infantry sucks. No IED's on a Carrier to blow up. No lugging body armor & 80 lbs. packs up a mountainside.