Neverwinter

Manycoin's Bank Heist is a Skirmish you unlock at the end of the Acquisitions Incorporated campaign. The skirmish also requires an item level of 14,000 or higher, so you'll need to have played additional campaigns besides Acquisitions Inc. and the base game.

The skirmish goes by pretty fast. It's divided into 3 parts, but all you're really is defending the center. Through out the first 2 parts, enemies spawn in 1 hallway at a time, except the one your group came from. You can do additional damage by picking up blue mines that the map provides and guarding halls with them. In part 2 it starts out the same, but eventually they start spawning in multiple halls. You'll also need to close off their spawns as soon as you can. Part 2 will spawn Death Balls that chase a character around the room. If you lead a Ball to an enemy spawn portal, the portal closes. Part 3 is just the boss and some additional enemies.

So if you want Gold, kill what enemies you can. If you don't see any, check the other side of the room. Mines can be left planted waiting for an enemy to walk to them, so they aren't worth being used to spawn kill enemies. Putting them at the end of a hall just takes up time you could be using to help teammates. If the Death Ball is following you, find an open portal and close it immediately. Last thing, you don't need to get Gold on all parts, just need it for most parts for the end result to be Gold. Unlocked this achievement with Gold in parts 1 and 2, and a Silver in 3. Good Luck