Defendant: "It takes practice but it is quick..."
Defendant: "I didn't want to drag the gun and an extension cord outside for two joints..."
As a firefighter, fire marshal, fire coordinator, code enforcement officer and county fire commission member, I have never seen a house fire started accidentally by someone using the proper heat source for shrink tubing.
I have, however, and unfortunately, seen house fires started by the injudicious use of open flames.