Fuck You All!
When Jake had an idea, he could be pretty damn thorough to get it done. In addition to digging a discharge tunnel for the lava pouring directly above the sacrificial altar, he also created a branch-off tunnel for the lava coming up the volcanic conduit from the depths of the earth. This channel would lead to the fortuitous emergence of a lava fountain right in the middle of the crowd.
He had tried to dig directly beneath the temple, including under the sacrificial altar, without success. The catacombs beneath the altar and temple looked more like a giant vault than a simple basement. He could now bend the rock to his will, but such thick metal was beyond his grasp.