Roy was one such person in hiding, but he wasn't about to let himself get flushed out this early in the game. With a simple transmutation, he timed it so that a small patch of plants caught fire just as thunder boomed across the area. He then followed that up with another transmutation.

Not many people knew that the transmutation circle on Roy's gloves actually moved oxygen rather than conjure flame. Roy used this to his advantage to alter the oxygen's bonds. The end result was a cloud of ozone rather than oxygen gas. The odor could be detected for quite a ways. That should throw them off.