As a Deputy Sheriff and military guy I have been tasered for the full length of time possible. I was shot with one electrode in my left shoulder and one in my right hip area. The farther apart the electrodes, usually the more the effect. I volunteered for the shot for training purposes. I have actually taken a taser three times if you count holding the electrodes too.
I not only stayed standing during the shot, but was able to draw my right shoulder muscle up to try to draw a gun while being shocked by the taser. I was screaming very loudly while getting shocked, but I did stay up.
I would rather get tasered than pepper sprayed any day of the week. Pepper is way worse in my experience.
Something else must have happened to these persons in addition to the taser.
I was exposed to CS gas once. It was one of the worst experiences of my life.