I did the 8404 Field Med course back in 1988. It was good class in basic first aid. We could do a ton more stuff on active duty but the basics were just hammered into us because they save lives. And before someone says anything negative about it, try remembering your basics in the dark with live ammo and arty going off, gets just a tad hairy.
Playing in the mud with the Marines was fun. There are some things you will only see in the service because they happen so infrequently in the civilian sector.
As far as enlisting, consider the Marines new advertising slogan, "We don't accept applications, only commitments." The military is serious. It is not a McJob you can just quit because "OMG that big sergeanty guy is a meanie who, like I swear, ate one of his own children for breakfast." OR "Camouflage makes me look fat." OR "It's like SOOOOOOO hot in the desert, why don't we like invade the Bahamas."
The skills you learn there will be put to use in worse conditions than you can imagine. So before you enlist consider your dedication to learning and serving your brothers in arms and your country. Non-hackers will be sent packing and you do not get to pick where you go.
One more thing to consider... more Congressional Medal of Honor recipients have been Corpsmen or Medics than any other group and almost all of the citations are ended the same way... "post-humously awarded this date..."
It gives a new meaning to the phrase, "So others may live."