Sign up if you're level 50.
Room for 10 people in two summoning groups of 5.
Each team will pop 3 bosses - this means each person in each team will also get the mission reward on those 3 that are spawned by the team (= extra loot!)
If you find yourself forced to mercilessly slaughter your teammates because they become infected with some rare mutation, keep in mind that you are only doing your job -
They would do the same for you.