People sometimes have a helper 'guide' the auger, a very dangerous practice. It sounds like the tractor operator may have dismounted and tried it himself, but there really isn't enough information available to say exactly what happened.
However, I will now mount my soapbox and state that in my opinion, a whole lot of deaths and injuries could have been avoided if we had a decent PTO shaft safety shield. The current 'metric' PTO shields are junk, with plastic eyes for the anti spin chains that break if you look at them, and they are a pain in the rear to deal with. People take them off because of their poor design. If the design were better, we would see more people using them, and fewer deaths and injuries.
/soapbox