A manlock is a specialized decompression chamber used in deep tunneling, caisson work, and mining where the work area is kept under high air pressure to hold back water or unstable soil. Workers pass through this chamber to gradually acclimatize to the pressure changes, preventing decompression sickness. It is strictly regulated and monitored by safety personnel.
Heard on the job
The crew is cycling through the manlock right now, they should be on the surface in twenty minutes.