Breaking Point

Primus and Charlie Kingman arc spending 60 days in the undersea habitat Tektite II with three astronauts while they prepare themselves for a life on a manned space laboratory. However, as time elapses, Marshall Grant, one of the astronauts, begins to crack under the stress and strain of the mission and barricades himself in the wet room. Before Primus and Kingman can reach him, he switches off the life-giving supply of oxygen being fed to the habitat, endangering all.