I’m not sure that you do. Pretending to not understand something you then say that you did understand is not sarcasm. It’s more like feigned ignorance. And while I guess that can be used to point out that something is unclear, in this case the thing was clear, so the ‘joke’ didn’t really land
Saw that video and never found any info on if he recovered. My first reaction was holy shit that’s going to hurt and be messy, but some comments were saying about the heat of the iron (it’s not supposed to still be glowing bright red, it was WAY too hot), length of time, pressure, and proximity to vital organs means that he likely wouldn’t survive it…