At the end of the day, I don’t trust any gcode (because I can’t really review it) and I don’t trust any firmware (this isn’t safety rated at all, and the boards they run on are also not safety rated). The parts can fail-closed (meaning they would leave the laser running). They can just freeze computation (which would also leave the laser stuck on). Or they gcode could just be wrong and it would be doing exactly what was in the file, and start a fire.
So I don’t trust my CNC as far as I can throw it. The fact that is usually works makes me trust it even less. If the one time it doesn’t, it destroys my garage, then I can’t leave it alone. The router is 600W+. The laser is obviously more dangerous looking, but that much energy can also turn your shop into a pile of ash.
Close call. I’m glad you’re safe.