Nanomancer #1

Imagine a world where technology has advanced to a point where it is indistinguishable from magic. A few muttered commands from a person and the nanobots in the air come alive and begin constructing or destructing whatever the user wills. Now, the nanobots have escaped. The world is coming to a fiery end and only one man can stop it, but since he set the fire to burning to begin with why would he?