So after working on it for afew minutes, I turned off the heat gun and took a look.  It seemed ok, but somehow, not quite dark enough, especially in the face.  

So I turned on the heat gun, and got back to work.  At this point, I had to be careful.  Burn it too much, and I would ruin the tortilla.   And if I ruined the tortilla, I knew I would fly into a mindless rage, probably driving to the edge of town and getting into a fight with some trucker in the men's room of a rest stop.  And I didn't want that.  

So I would have to be careful.