How about capture the medic?
Everyone splits into teams, or goes on their own. A team of medics is released into the map (Or a certain area - depends on number of players and medics), and given a grace period of 5 minutes. The only vehicle they are allowed is a hatchback (Or maybe just on foot). Meanwhile, the teams are supplied with zip ties and rubber bullet guns and prepare for a chase. After 5 minutes has passed, everyone has 1 hour to find, capture, and return atleast 1 medic to the Kavala Hospital. Along the way the captors (who could keep it secret that they have a medic) are allowed to be attacked by other teams.
Prize = ??? Lollipops? money? Medical item??