I'm legit not sure what we're looking at here. It echos in the gym, but so does a TKD orange belt slapping shit. It hurts the pad holder, but he's a goof and also selling it like a professional scam artist. He doesn't particularly have devastating form, so I can't be like "oh I bet that hurts cuz it's so technically perfect".
He may very well be able to kill me in one kick (likely considering his reputation), but I don't know how to tell from this video.
If he wants to show off, it needs to be against at least on a heavy bag or an opponent with some sort of decorum.