There’s a difference between being safe and being reckless. Using one of these is dangerous. The flame can easily seep into the can and make the whole thing blow up.
I am sorry about your friend and saddened that some think this is a cool idea and evidently anyone who does not approve of playing with fire is a wimp. Someone who who works with a fire department or emergency room could tell anyone who would listen that “experiments” with fire often have bad consequences.
This is like holding an incendiary grenade in front of your face and tampering with it and hoping it does not explode. Really bad idea.
Horsepucky. There is no oxygen in the can.
“The flame can easily seep into the can and make the whole thing blow up.”
No it can’t.
There’s no oxygen in the can and you can’t burn without oxygen.