Down below, Vakama watched Onewa's fall with horror. None of his disks would help in this situation, and melting the slab wouldn't save the Toa of Stone.  But there had to be some way his elemental power could help.

Then he remember something form his lifetime spent around heat and flame.  He reached out with his Toa energy and began to heat the air beneath Onewa.  Hot air would create an updraft that would slow the Toa's fall, Vakama was almost certain.  It wouldn't save him, but it might buy him time to save himself.

~Greg Farshtey, Trial by Fire, pg 87 - 88