"Here - hold my beer!" Probably a high school physics teacher......probably not a mechanical engineer.
There are things in the world you just don't need.💀
Very fascinating and pretty impressive - until it failed. I have one just like it, but no liquid nitrogen.
"Oh crap I cant stop it" ...don't worry , that problem will take care of itself !
Looks like he filled it all the way to the top - maybe it would not have failed if he had used a bit less liquid nitrogen?
Lol, I think you are right, the manual should state the correct amount.