Nice video, now we know that we have to wear laser glasses when we put our head inside the machine while running 
MMmmm this test from someone who’s laser cabinet is made of clear material???
I wonder why we keep discussing whether laser safety glasses and interlocks are important. I doubt that we would be having this debate as to whether you should wear safety glasses when grinding or welding or … sigh!
@donkjr His cabinet isn’t clear, it’s non-existent. He got the thing working then stopped.
He also likes to store plywood sheets under the honeycomb bed. XD
Well, watching his videos seems that he knows what is doing, regardless his setup. Also, having a clear cabinet is not important, as long as the material stops the laser.
He tests with the focused beam too, you have to crawl into your machine and put the eye into the beam path to have that kind of injury.
Impossible to get that results from a scattered beam, or unfocused reflection.