On February 4, US Navy Seaman Kyle Mullen died after completingHell Week, a notoriously difficult part of the training for US Navy SEAL candidates. On the same day, another candidate was hospitalized.

The Naval Special Warfare Command said in a press release that Mullen and his classmates successfully completed Hell Week earlier that day and that he was not actively training at the time of his death.

The cause of death was not known and an investigation was underway. The inherent dangers of special operations are highlighted by the unfortunate event, where the risk of death or serious injury is present both on the battlefield and in training.

Death in Hell Week

Navy SEAL candidates participate in an exercise during "Hell Week."
Navy SEAL candidates during a Hell Week exercise.
Richard Schoenberg/Corbis via Getty Images

Hell Week is one of the most well-known parts of special-operations training.

The First Phase of BUD/S usually begins on Sunday evening and ends on Friday morning.

In the event of a medical emergency, there is an ambulance near the students. If needed, the Navy SEAL corpsmen are ready to help. Students go through a medical check every day during Hell Week, as Insider understands that instructors and staff work together closely.

During Hell Week, all instructors are educated on risk and injury prevention. Bob Adams, a retired Navy SEAL officer and doctor, told Insider that there are medical personnel present 24 hours a day and doctors conduct regular full-body checks to evaluate for pneumonia, cuts that are infectious, and signs of disease.

After 12 years in the Navy, Adams went to medical school and became a doctor in the Army. In his book Six days of Impossible: Navy SEAL Hell Week, Adam details the incredible pressures that Hell Week puts on the body.

navy seals hell week
BUD/S students train with logs during Hell Week, in Coronado, June 22, 2003.
Handout/Getty

Adams said that Hell Week can leave lasting effects on those who go through it.

Our core body temperatures at times dropped below 90 degrees (98.6 is normal), and now many years later, all of us have core body temperatures below normal.

Navy SEAL students are trained to overcome adversity and push through.

It is in the BUD/S mentality to "suck up the pain" and move on with your job. The realities of the training regime encourage students to hide or deal with injuries while in training, according to a former Navy SEAL officer.

The former officer said that the training was not stopping because of the injuries because students don't want to get rolled back.

A dangerous profession

Navy SEAL BUD/S Hell Week
SEAL candidates during BUD/S training in Coronado, January 23, 2018.
US Navy/PO1 Abe McNatt

The risks are not over with Hell Week. Students spend most of their time in the pool learning the basics of combat diving.

It is a difficult time. The event at the end of Second Phase can force students to start over or drop out. Shallow-water blackouts are common throughout the second phase. Students are given the chance to handle live explosives while sleeping.

A former enlisted Navy Seal told Insider that he would be more tired and hungrier in the SEAL Teams than in the BUD/S.

Students will hear that a lot during training, but they don't really believe it when they see how cold it is in the middle of the night. It is true and accurate. The former enlisted SEAL said that life in the SEAL Teams is worse than BUD/S.

The Naval Special Warfare community has had two fatal training incidents in the last four months. The commanding officer of the Navy's elite Seal Team 8 died of injuries he suffered during a nighttime fast-rope exercise in Virginia Beach.

Training deaths are not common for the Navy SEAL community.

It is a dangerous profession at the end of the day. Training for it is dangerous and doing it is dangerous because of the high demands of the job.

When there is a maritime contingency, US Special Operations Command calls on the Navy's SEALs. The training must be hard.

A defense journalist specializing in special operations, a Hellenic Army veteran, and a graduate of the University of Baltimore, are some of the things that Stavros Atlamazoglou is.