Once you select a mission on public, you have to go to the elevator and start your way up. As soon as the public players have joined, you leave their team and start your own "team" in the same loading time (elevator ride). When you reach the surface, you can select a bounty from the bounty dealer directly outside, this starts 2 bounty's at the same time. This causes issues with the hacking missions (doors will not open). Rewards are given for the parts of the bounty you completed.