On Dam Battlegrounds, visit the Locked Room in the Water Treatment Control building

How do you complete "On Dam Battlegrounds, visit the Locked Room in the Water Treatment Control building"?

This is step 1 of 3 in Greasing Her Palms, given by Celeste. It is completed on Buried City, Dam Battlegrounds and The Spaceport. The exact location is marked on the Buried City map.

• Greasing Her Palms
• Buried City
• Dam Battlegrounds
• The Spaceport

What are the other objectives in Greasing Her Palms?

Greasing Her Palms has 3 objectives in total: On Dam Battlegrounds, visit the Locked Room in the Water Treatment Control building, On Spaceport, scope out the rocket thrusters outside the Rocket Assembly and On Buried City, visit the barricaded area on floor 6 of the Space Travel Building.