Second article, Six Thai Boys Rescued from Flooded Cave

...Six of 12 schoolboys have been rescued so far from a flooded Thai cave after divers launched a daring and dangerous mission to free the children and their soccer coach, who were trapped underground for more than two weeks, Thai officials said.
"I have received information that six have exited the cave", a senior member of the rescue team told Reuters. ... Thirteen foreign divers and five members of Thailand's elite navy SEAL unit are trying to bring the rest of the boys ...

From reading it appears the decision was made because with water levels in the cave lowered, parts of the cave were walkable and waiting would only allow the monsoon rain to fill it back up. Somebody made a decision to go for it.