To start an Isolation Vault bounty, players must first talk to Mother in the Necralisk or at the first tier Mother here (refer to this map for subsequent tiers of Iso vaults). Upon starting the bounty, you must first gather Fass/Vome residue (based on the current cycle); the amount needed will scale with the amount of players currently in the squad, and the residue will be inside yellow objective bubbles on the map. You will only ever need to complete a specific Tier of Isolation Bounty once to unlock the next Tier.
1-2 players will have you gather 6 residue.
3-4 players will have you gather 12 residue.
Once players have gathered all the necessary residue, you must bring it to the way-pointed bait station. After defending it for 90s, you will have to take the mixture into the caves and throw it at the “monster door” wall blocking your way. If you miss or fail to hit the wall, you will need to go back to the bait station and create a new mixture; you will not, however, need to recollect residue to do so.
After you hit the wall with the mixture, a path into the cave depths will open; a Toxin meter will appear on your screen, and the passage forward will be blocked by another “monster door” wall. This meter will scale from 0 to 100, and gradually increases by 1 every 0.5 seconds. During this stage of the bounty the player must survive for 90 seconds while killing enemies. If you want to reduce the toxin level, pick up the special drops from way-pointed enemies. This will reduce the build-up by ten. Keep in mind that if all players of the squad aren’t in the designated way-point area, the toxin level will increase more rapidly.
Once you’ve successfully fended off the rest of the infested for 90 seconds, proceed down the cave system. The next part of the bounty will have you kill an enemy Necramech; the amount of mechs equals to the tier of the bounty.
Enemy Necramechs can only be harmed when hit in the shoulders or the void markings on their back. Weapons that have punchthrough on them will help a lot because they will be able to attack no matter the firing angle. If you break both of their arms, the Necramech will immediately charge at you and use storm shroud & grave mines. Be careful of this since it can quickly kill unsuspecting players. Once you kill the mech(s), an “Esophage” will appear and be way-pointed. If you want to skip the bonus rewards and just take the bounty rewards, take the esophage up to the surface.
For the bonus phase, you must have completed The War Within. Find the vault door in the area which looks like this (Tip: It’s generally in an offshoot in the infested tunnels around the vault). After you find the door, hit the Reactive Crystal with your operator’s void attack; this will spawn Loid and start the next part of the bonus phase. Loid will activate the 4 Reactive Crystals around the vault; defend him from the Infested while he does so. Once Loid has returned to the door, he will despawn and the door will activate with a pattern of Requiem symbols on the door. You will need to memorize the symbols on the door from top to bottom. You will have 3 chances to input the correct sequence or you will be locked out of the vault. Hit the Reactive Crystals with the symbols with Void damage in order to activate them.
Upon successfully completing the bonus phase, you will be awarded an additional drop from the rewards table and the vault that opens will have breakable containers with many Cambion Drift resources.