Journey to the Center of the Earth- entry 6

I believe that this part of the book is the climax.  Or at least the begining of it.  They are puzzled by the skeleton and so am I.  The team also found a dagger in the cave and that gave me the immediate clue that Saknussemm was in that same spot.  So they take the cave that was thought to be the same way taken by Saknussemm and find a dead end.  This puzzled me that if it was a dead end he could not have taken that route.  So they make a cavity in the wall and fill it with gunpowder.  Then Harry lights the wick and runs to the sea and joins his Uncle and Hans on the boat.  The explosion caused an abyss to appear in the water.  This part really caught me off gaurd.  The abyss sucks them in and they freefall fo a couple hours before landing softly suprisingly.  Now they are being drove up and soon go out the top of a volcano.  How would youlike to freefall?