Just make sure you get locked into an MOS before you ship out and don't go in open contract. Security Force should keep you busy, but from what I understand as my buddy did it, is that Security Force isn't an actual MOS, it is a secondary billet, but it would be under an infantry type MOS. They may have changed that since I was in, but it was a 3 year billet that you could start off in or lateral to at somepoint during your enlistment.