From what I have read the connecting passages within this cave system are not of the "walk through" type, they are more "crawl through". So a "chamber" is a big "room" within the cave system but to go to the next area you have to crawl on your belly into a small hole that leads to a long narrow passage through the rock to the next big chamber. The long narrow crawl passage may have turns and places that become very, very narrow where a rock sticks out of the ceiling or the side wall. It could have some water running through it, even during the dry season.
One description I read of this cave was that at places the passages were too small for the divers to have an oxygen tank on their back. So that is a tight passage, for sure. These boys will need to be fully conscious and participating to get out of where they are through flooded passages.
There are caves here in Pennsylvania known to be "a long muddy crawl". Yuck. They are not the Luray Caverns! Southern West Virginia has some really huge dry cave systems. But I still would never go into any cave, wet or dry, when it was due to rain.
The same article said it takes these experienced cave divers 6 hours to get from the entrance to where the boys are. They are "swimming" through areas of flooded narrow passages going against a swiftly flowing water current. So it is easy to see how highly risky the "swim out" solution is as an option.
The "wait it out" solution could be risky also. No one has ever stayed inside that cave at the area where the boys are to know whether or not it remains dry throughout the rainy season. As more and more rain falls, that area could become flooded also, so that is a risk.
What about drilling down to them from above and bringing them up in a rescue capsule like they did here in Western Pennsylvania at the Que Creek mine and also at the Chilean mine? The illustrations show they are about a half mile under the surface - so about 2600 ft. of drilling.