Step 2: Apply heat
I learned pretty quickly how to apply this heat. I found that if I heated the paint too much, it would simply harden and make it just as difficult too remove as pure sanding it would. I also found that after you apply the heat, you have to wait till the paint cools otherwise it's a big gooey scraped mess :/
The best way I found for this door (YMMV) was to hold the gun about 6" away from it, let the paint bubble just a little bit. The paint would seemed to generate some fumes (safety note, do make sure you are in a well ventilated area) and the paint, being evening applied and sufficiently think enough, would start to create one big bubble underneath. This is the paint literally separating from the surface and is ideal for removing.
I also learned to do it in small sections as the 'bubble' would eventually find a part where the fumes would escape and collapse, thus partially ruining a clean removal.