On June 23, a youth soccer team from Thailand found themselves trapped in the Tham Luang Cave after heavy rains pinned them inside. 12 boys and their assistant coach had been perched on a ledge inside the cave when two British divers found them on July 2. Four of the boys were rescued [VIDEO] on Sunday (July 8) in what was a nine-hour journey through the cave, wading, and climbing through narrow passages and flooding water caused by the rains. Four kilometers down, escaping the cave has become a tall task, not to mention "some of the most extreme conditions ever faced" as described by the divers.

The rain becoming the rescue's worst enemy

It was supposed to be a fun excursion for the Thai soccer team from the Chiang Rai province, but it turned into a nightmare.

Even with 90 divers [VIDEO] working as a team to ensure the rescuing of each member from the Wild Boar soccer team, it has not been an easy process.

The Chiang Rai province is expecting more rain in the coming days that could increase the water level in the cave and make the trek back to the cave entrance more difficult. Rainfall could potentially seal the cave entrance, making it impossible for the diving team to rescue the remaining boys and coach until October. All would depend on the water levels. The first four boys were able to successfully make it out of the cave easily because the rain stopped on Sunday. Depending on the amount of rain in the next few days, things could get even more difficult for the 90-person team.

Lack of oxygen

One former Thai Navy SEAL named Saman Gunan ran out of oxygen during the cave rescue mission, after trying to deliver oxygen tanks to the trapped soccer team.

He lost consciousness during the trek and eventually died. "Oxygen levels (in the cave) have plummeted dangerously to 15 percent," according to Susan Scutti from CNN.

The rate at which the oxygen levels decrease could determine the soccer team's survival. Nausea, vomiting, and confusion are all symptoms of a lack of oxygen. According to the US Department of Labor's Occupational Safety and Health Administration, the "optimal range" of oxygen needed in the air needs to be between 19.5-23.5 percent to maintain normal function.

Carbon dioxide is another factor the team fears that could affect the coach and the boys. The rescue team will continue to provide oxygen tanks for the soccer team, but they hope to bring them home as soon as possible.

A narrow escape

The Tham Luang Cave presents a variety of obstacles for both the divers and the Wild Boar soccer team. The distance is four kilometers to the cave entrance, 2 1/2 miles from where the coach and the boys were found. Some of the children can't swim, making the journey back to the entrance a lot more difficult.

On the way back to the entrance, the most difficult part is a narrow passage called the "T-Junction." This particular area requires divers to take off their air tanks because of the tight space. Divers, the children, and the coach will have to wade, dive, walk, and climb on the way out. Add to the obstacles the flooding water, and you have a rescue mission that with one slip up in the plan, could cost the remaining lives in the cave.