Bandit 1890 xp "Intimidator" is shown in the video clip.
Shovelling in debris? I cannot fathom how you could fall in unless you were alone at the apron and were struck by a branch which knocked you onto the pile going through. It is over 5 feet from the edge of the apron to the feed rollers.
The 1590 and 1890 chippers have reverse "control bars", last chance pull strings above the apron and if you have a winch a hydraulic flow control which shuts off the feed wheels when winch mode is selected. All within easy reach of a "buddy" operator. Over here OHS requires another pair of emergency stop switches to be fitted after import so there could well have been 4 methods of stopping or reversing the rollers.
Just a word on age. My son has been working with us on school holidays since he was 15. I cannot describe the fear I felt when he threw his first branch into the chipper. It was watching him do this that made me review every aspect of chipper operation. If you have children I don't need to explain why. These machines are deadly. Please think about what you do at work tomorrow.