I used to smoke whilst driving, not in the zed but in my mazdarati i had before it, and i don't think its dangerous, lighting up can divert your attention but if i had a passenger i would always get them to light one for me and pass it to me.
had the end fall of a tab whilst driving before and it was a simple case of pull over and make sure it was out. there is always somewhere to stop.
as for the make up girl, at least she was using the rear view mirror and not the vanity mirror in the sun visor, which i've seen, and like nixy, nearly got out and told the silly bitch off.