I will take a guess of why this happened if it is real.
Probably happened in the winter time when the outside temperature was cold and there was no heat inside the shop.
Since it was so cold inside the shop, the operator needed to wear two shirts and a sweater to feel comfortable to work.
Of course the sweater got caught and pulled him in.
Good guess.
I saw several accidents when I was a machinist.
Guy with long hair didn't have it tied up because 'he was only running a drill press'. Got caught on the old greasy spindle and scalped him.
Another guy on a boring mill. Interrupted cut on a pull-down cam. Was taking a file to knock off the burrs as it came around. No problem, except he had the sleeves down on his long sleeved shirt, it got snagged and dragged him into the cutter. Lost arm above elbow but he was lucky. Pretty gross , one of my bosses puked.
Another guy didn't secure a large (forget the name but they were exhaust tubes for missiles on a ship, part of the Navy's VSL). one toppled over, crushed another guys legs. Both amputated and a couple months before he was to retire.
A guy was changing the wheel on a heavy duty bench grinder. Instead of winding the nut by hand to tighten it he turned it on to speed it up. Not a horrible idea EXCEPT he had gloves on. The nut tightened the tips of the gloves to the wheel and ripped off 2 fingers and his thumb.
About the worst for me was a chip in the eye. I was deburring some bronze pieces on a belt sander. I wear glasses so I generally don't wear safety glasses. Well a chip bounced off my cheek, then off the inside of my glasses and into my eye. The sucky part was its was bronze so no using a magnet to get it out. I went to Wilmers and they had to buff it out. Really freaky hearing that high speed grinder coming at your pupil then hearing it bog down on your eyeball.
Oh did have another. Cleaning up the back chip pan of my CNC. Someone clowning around threw someone and it was just enough to make me flinch. My hand hit a brand new end mill in the carousel. Big gouge in my finger. The cut didn't hurt horribly but when the Doc stuck a needle in that open wound to numb it before stitching, the only thing touching the gurney was the back of my head and the heels of my feet.
Pay Attention!
Its easy to take some this stuff for granted. I have to constantly remind myself and watch where my body/face/hands/arms/etc.. are going and where they'll be if something breaks, jumps, I slip, etc..