The video is what, 4:30? Fast-forward, if you can't afford the time-commitment. it's the double-arrow button on your VCR.
Works well, that idea, cheaper than the Dremel blades. Unexpected wear on the oscillating tool mounting is something to watch, as-mentioned.
I don't know when I'd need that capacity, but it sure is something to keep in-mind. When I saw the silhouette cut-into the carpet, I thought, "Colonel Mustard in the study, with the candlestick holder!"