Sounds dangerous.
https://www.agas.com/uk/products-and-services/refrigerants/r...
Ticklish though I'm sure to do it properly and safely.
You may be thinking of acetylene. But that isn't really that dangerous in modern usage either.
It doesn't have to explode to burn you though. Where is the purge gas escaping when used this way?
I have no idea what you mean by "purge gas".