Eruption
The compass has gone mad, jumping from pole to pole in sudden jerks. The manometer is missing so they do not know how deep they are. To make matters worse, terrible detonations can be heard but not seen to one side. They are loud enough to make the walls of the shaft shake. Is all lost?
Harry is terrified but the Professor remains calm. They may be riding a volcanic eruption, but it is their last chance to escape the interior of the earth.
The heat becomes intense. The temperature of the water below them reaches 190 degrees Fahrenheit. As it boils away, a lava paste is revealed underneath.
Torturous hours pass and the group reach the limits of their endurance. Further, the trusty raft finally begins to break up. Just when all seems irretrievably lost, they suddenly emerge into daylight. They find themselves in a secondary cone, low on the side of an erupting volcano and thankfully scamble to safety.