Samantha, thrown by xistera, got Emberus to hurl her into the volcano exactly as planned — and it worked.
Samantha came back reporting the outcome herself: "pretty wild," Emberus was going to eat her, but he threw her into the volcano like Carl said he would. Now he's blowing up the world, so they should probably go.
The cost was Samantha, burned ten times worse than before and barely recognizable, and the result was a three-minute countdown to the destruction of The Ninth Floor, with red comets from the exploding volcano streaking overhead and the heat becoming unbearable.
The gambit that provokes Emberus into destroying the ninth floor, executed exactly as Carl predicted.