Actually no, you do not have to die from something deadly. There are many ways to survive something that is deadly. For example if you continueally inject yourself with a rattlesnakes venom in small doses you will eventually become immune to its deadly venom (or at least immune enough to not die from it). The reason that you become immune to it is because you build up a tolerance to that venom. Your body will eventually inhibit the effects of that venom. This does not mean that if you get bit by a rattlesnake that the venom is not deadly because it is still the same venom. Your bodies defenses will just inhibit it. The only difference here is that it is the THC doing the inhibiting of the deadly carcinogens and not your body.