Nonstick Pan Ruined in High Heat?
Yes high heat can burn off the nonstick coating.

My roommate's girlfriend did one of my pans that way, heating it very hot while dry.  It was pretty spectacular.  Everyone in the house had this weird little cough like from dilute pepper spray.  Anything silver in the house tarnished.  I presume the nonstick was burned off and floated around in the house, causing these effects.  The pan was still usable after, just no longer nonstick.