I have to dis-agree. Look at the top of the tail boom---it appears the metal is bent out. I suspect had the blade have chopped of the boom then it would have entered at about a 45 degree angle.....and the top and left side would be bent in.
Compare to these pictures are from a tail boom that was cut off by a main blade---admittedly this is not an R-44 and this occurred during a flare gone bad--so not at altitude, (not me btw---but I did investigate it):
