Mid safe room of the Oasis.

Found inside the secret area of the Ruins.

Inside the mid safe room on Fields behind the Tech Room Key door.

Sold by Heisenbot for 9 Powercells.

Found in Aqua Center after completing (entering from) Doom Garden.

It's right there.

At the mid safe area in Energy Center is a lab locked behind a key door. This key can be found after exiting the level "Doom Gardens" and entering the Aqua Gardens. Refer to the Power Crystal section for how to access this level.

Inside will be a glowing orb and a screen showing 2 digits of a a 6-digit code. To reveal the other numbers, you must damage the orb with fire, cryo, and shock damage. This can come from both weapons and abilities, such as the Engineer's elemental blaster upgrades. The Jigsaw box corrupted item can also re-roll your weapon modifiers until you get all elemental modifiers. Chef Paul can also spawn outside the room, who can reroll weapon modifiers for a cost.

You must then take this completed code back to the starting area of Energy Center and input it into the locked door. Grabbing the Prismatic Cell inside will unlock the Elementalist.

In the room before the boss on The Pit.

Inside the locked code door at the start of Energy Center.

At the mid safe area in Energy Center is a lab locked behind a key door. This key can be found after exiting the level "Doom Gardens" and entering the Aqua Gardens. Refer to the Power Crystal section for how to access this level.

Inside will be a glowing orb and a screen showing 2 digits of a a 6-digit code. To reveal the other numbers, you must damage the orb with fire, cryo, and shock damage. This can come from both weapons and abilities, such as the Engineer's elemental blaster upgrades. The Jigsaw box corrupted item can also re-roll your weapon modifiers until you get all elemental modifiers. Chef Paul can also spawn outside the room, who can reroll weapon modifiers for a cost.

You must then take this completed code back to the starting area of Energy Center and input it into the locked door.

At the start of Waste Station.

Inside the Quarry behind the locked door. Your code will be random.

Directly in front of the tunnel.

Directly above the tunnel behind a truck.

Right next to button 2, on the underside of the billboard.

Inside the tunnel itself after the second gate.