Neat Idea... BUT
Points off for using a cut-off wheel to cut out the door without there being a guard on the cut-off wheel. See step #3. I've got what looks all the world like a sharks bite scar on my right leg from a wheel that disintegrated even before starting a cut and that was with a guard in place.
Trip to the E.R., about 16 stitches, and I was very lucky. Without a guard it could have done a lot more damage.
Never use a cut-off wheel without a guard.....