Agreed but I think he was just throwing it out there for discussion. And for the record, chloroform is not like getting tased where you immediately lose voluntary motor control ( usually ). Any gaseous agent like that has to reach critical concentration(s) to elicit the desired effect, no?

Might take a few seconds or if the windows are down and the car is moving at road speed it might not happen at all. Or so it seems to me.
My own thinking runs toward a prank I heard about many years ago where a vile smelling liquid was sealed inside a plastic bag ( vacuum storage bag as I recall ) and rigged to be slit on four corners by razor blades when the lid of the two part box was raised off the bottom section. I think the box used was a modified apple box or something similar. The box was not airtight or water tight and the liquid would immediately run out of the lowest corner of the box through four, small, strategically placed holes.
Apparently the target of this prank was not highly thought of and managed to really pi$$ off somebody so they brewed up some truly vile stuff and came up with the delivery system and had it delivered to the guy's house with a very legitimate and official looking return address. The story goes that his wife took the package inside and set it on a table and later when she talked to him on the phone and asked about it he told her to go ahead and open it while he was on the phone with her. The subsequent cussing and screaming caused him to call the cops and bail out of work for home at best speed. When they all arrived the wife was still puking in the front yard and nobody could stand to go in the house because of the smell. Apparently the prank made the evening news in the small town where this happened and was talked about for a week.