Many moons ago I worked at a computer service shop that also repaired CRTs. Once, as a practical joke, someone asked me to hold a lead... Which was live with around 4kV. Wasn't pleasant experience.
You probably saw the tool used. A long flat blade screwdriver with a wire wrapped around it and on the other end an alligator clip chassis ground wire. It's used to pry up and remove the high voltage lead and when doing so you'd hear a loud snap!