This may help those who are confused by what you're supposed to do regarding the extra objective.

In general, Central or Monst3r's dialogues will provide the cues you need, there are also tooltips that will help.

The new Omni Shield Generator is a device in a new custom room. There is also a new room with several crisscrossing laser grids and locker vaults. They can be looted for extra loot, but this is purely optional.

The Omni Shield Generator device needs to be hacked (or EMP'd) and looted in order to disable it. After you hack it, it will immediately start rebooting over 5 turns, so act fast!

Warning. As the tooltips warn you, only Monst3r can safely disable the device!. (If you have the Merged Loadouts mod installed, and you have Derek instead of Monst3r, that works too.)

If any agent other than Monst3r tries to loot the device, they will take damage (which, barring some modded augments, puts the agent in critical condition). After this happens, the device will be safe to loot with a different agent until it reboots!

So you can have Monst3r loot the device, or send a two-agent team there instead, ideally with a medgel (or be prepared to abandon that agent... )