User blog comment:Neowitch/680 - "Two men walk into a lab..." Stop me if you know that one!/@comment-4754162-20120906043413/@comment-4493594-20120906105034

For the first one, logically it depends on the chemical reaction between the components of tobacco smoke (which I assume is the kind of smoke Smoker turns into) and whatever chemical compound Shinokuni consists of.

Looking at how the victims of the gas turn into ash figures, my guess would be that Smoker can survive in his 100% smoke form for a considerable amount of time but, since that stuff is supposed to be poisonous, he might get poisoned in the process which will affect his health when he turns back. Then again, tobacco smoke is fairly poisonous by itself...

Another possibility is that Shinokuni reacts with the smoke, weighting the particles down, slowly forcing Smoker to turn back into a solid form. But... that would mean killing Smoker in an even more gruesome way than the random guys. So scratch that one.

As for the second question: Yes, that seems like the most logical possibility.