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.