John, my best guess is that they probably were having some issues with this starter and had set up the camera for the test.
What I do find disturbing is that there were obviously at least two people in the room with this test (the camera operator and someone who is briefly visible on the extreme left of the frame right before the CO2 system fires off), which was a very bad idea. First because of the arc that occurred, and that it is unclear if they safely got out of the room when the CO2 did fire off.
I had the misfortune of having a CO2 cylinder that I was transporting in the cab of my truck,(one of my more stupid moments) with NO cover on the valve, discharge while I was parking. The CO2 filled the cab very rapidly and I began to "grey out" after only a few seconds, luckily I was stopped at that time and opened the door and got out. I was amazed at the volume of CO2 discharged in such a short time. I found out why it is an effective fire supressor.
I am registered with Youtube and will add a comment to see if the person posting can answer why there were people present during this incident.