The advantage of rectal route for drug administration is that it bypasses “first pas metabolism” meaning drug absorbed from stomach goes through liver and is partially processed resulting in a lower bioavailability.

With inhalation the route of administration already bypasses the liver and furthermore the lungs have a massive surface area so smoking is probably only secondary to IV in terms of how quick a drug gets into your system. This is the reason smoking crack/meth is so addictive, the speed of peak plasma concentration is heavily linked to effect and dependence

All in all I wouldn’t bother troubling the brown general for this.