1) Progress through the mission until the boss appears.
2) Clear the first wave of ads and have your friends fast travel to either The Firewall safehouse or the mission General Assembly (t his is closer). Have one person stay in the mission to trigger the boss spawn.
3) Have them head over to the gate where the boss will spawn.
4) Have the player that stayed in mission to activate the objective "Defeat Hornet".
5) Player that activates boss spawn will back track until they are out of combat and fast travel to where their friends have been waiting. *They should be at the gate by the time this happens
6) Kill Hornet. It will be quite an annoying task as there is a gate and lack of cover but with a group of 3-4 it will be easy if someone runs support.
7) After your group kills him, have someone run next to the gate so they are in the mission area (will say "No respawn zone") and it will spawn them at the checkpoint. Then repeat step 1-7.
*Do not enter the mission area when you kill him. You will NOT get drops for that round.
*Drops WILL disappear after a while, so figure out your own method to get the loot.
*If you or your group decides to complete the mission, make sure you are in the mission area or you will not get rewards for completing it.