you could in theory vapourise benzodiazepines, but the heat is likely to destroy/rearrange them, hence BA will be all over the map depending on vapourisation method and the particular benzo in question.
plus, benzodiazepines do not lend themselves to crack-type dosing through vapourisation. it's an incredibly easy route to overdo. vapourising benzodiazepines sounds to me like a great way to end up naked running through a snowstorm screaming racial epithets at the EMS staff coming after you. afterwards you will probably wake up in hospital with no memory of any of it.
put it this way: why is there any reason to vapourise benzos? they are well and completely absorbed sublingually/orally. smoking/vapourising them is just inviting waste, the potential for overdosage, and lung damage.
some people smoke tylenol 1's in bluntsand insist it makes them "more fucked up". that does not make it a safe or healthy thing to do.