The last word they heard on the two-way radio was Chuck telling them that they were about ready to descend into the tunnel and head toward the cavern. The next thing they would see would be the video camera operated underwater by Diana.
Chief Hollis was still trying to reassure everyone that what they were doing was necessary and important to the future investigation of the lower tunnels. He figured he had just about used all the money in the budget for emergencies and, if this idea backfired on him, he might even be asked to find other work when the council got done with him. But he thought to himself, "At least I’ll go out with a bang!"
Finally, the man he had hired to help with the video yelled that he was receiving a picture and he was recording everything that Diana was filming. They watched in utter fascination as they saw her swim along the tunnel. After awhile they saw the flare she was carrying, shine into the cavern. Walt and Chuck towed the heavy explosive bags and the timers to an area in the middle of the iron beams and started to work with the light of the flares they carried, while Diana went about filming all the angles of the huge cavern and the small cell she had found earlier on her first dive.
Chief Hollis could see why Diana was so upset at what she had found. It made him mad as hell just thinking about the possibilities of what might have gone on down there. Ben knew that creating a roof in that cavern was not done by just one man. It must have taken several men and some kind of heavy equipment to make sure the beams were in place.
Finally they saw Walt give the thumbs up sign and Chuck and Diana backed off as he set the timers for one hour. They gathered up their equipment and swam the distance back down the tunnel with the current.
Chief Hollis set his watch to tell how close the explosion time it would be when they finally lifted Diana out first with her video camera and all, then Chuck with the empty explosives bags and finally Walt with the extra air tanks on the bottom of the bosun’s chair.
They all got dry towels and made their way over to the house and stood off to one side, as the press was unrelenting in their attempts to get closer. The Sheriff and Police were having their hands full just trying to keep the people away from the opening.
Walt started the count down finally as the time expired and they heard his deep voice say "5-4-3-2-1-now!"
At first they thought maybe it hadn’t gone off, but then a loud rumble came from the hole in the pool and water shot up into the air about thirty feet as the cavern filled with the rubble from the ceiling.
Then they heard a sliding sound and a loud "whoosh"
as the rubble that had filled the main shaft slid down into the earth. They noticed a large circular depression start to form on one side of the new duplex and increased in size as the whole side of the building listed about twenty degrees and the roof split.
Walt said he had also put two charges at the entrance to the main tunnel to make sure it would seal off, as the water continued to flow from the air shaft like a fire hose. A large depression had formed under the railroad tracks and they could see the ties had slipped away, marking the main tunnel as it collapsed.
They could hear all the rumbling underground as it went on for a few minutes, then all was quiet except for the water that suddenly stopped shooting from the airshaft and started to drop back down into the earth again.