It varies by agency. On our team back in the early days of Tactical EMS, Medics were volunteers...actual EMT-P trained as tactical medics. We provided Advanced Life Support under the license of an MD as Medical Director. We worked in the inner perimeter and as part of the entry team. We were armed and armored. We qualified twice a year on all weapons used by the team, everything from the MP5's and M16s to the sniper rifles, to the M79 grenade launcher as well as our personal weapons. We were not sworn and did no law enforcement. We were armed entirely for self protection, as allowed by state law.