I "THINK" I saw the video you are referring to. The people look familiar and the guy was cutting shrubbery or something and there was net-wire fencing behind the brush, that was visible. The chainsaw kicked back off the wire--I guess--and nicked his shoulder. The young lady patched him up.
If this is the one, I called my wife into the room and run the controller back for her to see.
Don't see how it could have been "staged" !!
Thats it.

Yeah, no doubt it was staged,,,,,,,