"real" CS is nasty stuff. The Army used it to flush Viet Cong from tunnels. Didn't really work well, for that. Turned out that in high concentrations, the "flushing" was more "dying". Which, while the Army didn't mind killing, wasn't the mission statement, so they quit using it, for that.
The Army regularly gassed its own soldiers. Been there, done that, remember the burn.....,
And, speaking of burn, under the right conditions, CS will burn, releasing cyanide gas. Ask the Branch Davidians about that,...but don't expect any answer...
As to the "sparky things" only causing pain, it depends on the sparky thing. They run from the level of cattle prods on up to much more powerful devices. I watched a 300lb+ guy zap himself on the leg, to see just how bad it was.
He did a really good imitation of a fish out of water, slithered out of his chair to the floor and flopped about for what seemed like minutes, but was really much less time, maybe half a minute or so. don't know the exact thing he used to zap, it was decades ago, but I do remember, he said it wasn't PAIN that caused him to do that. It sure did hurt, afterwards, but it wasn't the pain, it was the electricity.