Underway on the USS Missouri - Deep below the surface, the sailors on the USS Missouri were working quietly at their stations when suddenly an emergency alarm sounded Friday afternoon.
Sailors quickly put on black breathing masks and gloves up to their elbows. They took the stairs two at a time and ran to their assigned damage control stations.
It turned out to be a false alarm. Atmospheric readings showed the conditions were normal throughout the submarine.
Any change to the environment is closely monitored because the inside of a submarine is such a confined space.
Cmdr. Timothy Rexrode, the commanding officer, decided to use the report of an abnormal atmosphere as a training opportunity and prepared to rise to periscope depth to ventilate the ship.
The Missouri (SSN 780) had just completed its latest certifications at the Atlantic Undersea Test and Evaluation Center in the Bahamas. Overseen by the Naval Undersea Warfare Center in Newport, R.I., AUTEC is considered a unique, natural deepwater range ideal for underwater testing.
The Missouri had been deemed ready.
The pilot and the co-pilot use joysticks to maneuver the submarine up and down. Early Friday it had descended to 500 feet. Later that afternoon, it was totally silent in the control room as the pilots brought the Missouri slowly up to near the surface as part of the drill, until the officer of the deck scanned the horizon and announced, "No close contacts."
The crew ventilated the ship and finished the drill. The officers and sailors returned to their posts, red marks on their faces from the breathing masks they had just removed.
Mark Painter, a sonar technician seaman, said earlier in the day that he doesn't think about his job as dangerous. He had just finished sitting in front of his sonar screen over a six-hour watch.
"They do a lot to make this ship as safe as they can," said Painter, 20, of Colorado.
A special breed
The rest of the drills Friday did involve simulating dangerous situations - firing on a hostile submarine and evading a torpedo "launched in retaliation."
Rexrode gave the order to "shoot on generated bearing."
"Shoot Tube 1."
Water shot through the torpedo tube. The air pushing the water out jolted the submarine.
The men in the control room rapidly called out commands and information as they tracked the simulated torpedo and the simulated enemy sub.
"Active homing, terminal homing," shouted the chief manning the fire control station.
"Torpedo evasion!" was called out in the control room in response to the simulated counterfire.
The pilots drove the submarine down 400 feet, ending the exercise. Rexrode said he enters training scenarios into the system to test their procedures.
Lt. Cmdr. Rusty Jones, the engineer, said it takes a special breed of warrior to serve on submarines. They get used to an 18-hour day instead of 24. They tell the time of day by the type of meal being served. But several said the camaraderie and the excitement of the job can't be matched anywhere else.
Standing in the middle of the control room, Jones coordinated the information from the photonics mast operator and the sonar technicians about nearby vessels while the Missouri was near the surface.
"Not everybody can do it," said Jones, 31, of California. "But our nation counts on our submarine force to do what others can't. So we on Missouri are here to do it."
Justin Tavis, an information technician, echoed that sentiment while he was waiting for his laundry to dry. He sat on the floor playing a handheld PlayStation to pass the time.
He has a picture of his wife on their wedding day taped to the wall by his bed.
"A lot of people don't want to be submerged. Most people think that when their ship sinks, it's a bad day. For us, it's our everyday routine," said Tavis, 23, of Georgia. "The Navy needs to project our power and maintain safety at sea."
"Many respond to the call to serve," he said. "We're just the ones that do it from the deep."