Trying to find a different rational, this is a military experiment to create ultra deep diving submarines and UUV's.
While current submarines are technologically very advanced, they are generally limited as to how deep they can dive. This essentially limits their ability to hide from detection to a limited "slice" of the ocean, perhaps akin to being limited to being able to hide on the skin of an apple.
With various rumoured developments in submarine detection being touted, it seems clear that some advance or combination of advances will eventually make the idea of hiding just under the surface of the water untenable. However, since the ocean is many kilometres deep, being able to operate in the entire 3 dimensional universe of the oceans means the volume which needs to be searched increases immensely, and probably beyond the ability of even the latest technologic to reliable track and locate enemy submarines.
The test, then is to put proposed systems for new generations of military submarines to the test, and the researchers are under contract to the Navy in order to test out this equipment under the sorts of conditions submariners may encounter. To this end, the sea lab is not just a scale model, but the researchers need to test equipment under simulated battle drills (i.e. could the crew work this under stressful conditions), ramping up the pressure to perform, but also to validate the technologies that some of these researchers have developed.
Failure means the end of lucrative research grants and possible contracts with General-Raytheon-Lockheed-Boeing-Colt-Oshkosh Co Ltd., so the stress is enough to push people hard, and inevitably some of them may be pushed the wrong way......