I thought class 4 lasers are dangerous even when they bounce off a rough surface? Why isn't everyone in the room wearing glasses?,(reply>), Apparently class 4 is very broad.,(reply>), I thought so too, this seems ludicrously dangerous.,(reply>)," @Rena Kunisaki <a href=""https://www.youtube.com/watch?v=tozuzV5YZ7U&amp;t=1m29s"">1:29</a> <a href=""https://www.youtube.com/watch?v=tozuzV5YZ7U&amp;t=3m05s"">3:05</a>; <a href=""https://www.youtube.com/watch?v=tozuzV5YZ7U&amp;t=3m18s"">3:18</a> is particularly unsettling as Tom is letting the laser reflect off his hand which is very close to his eyes.",(reply>), And are they just shining it on a bare wall?