"Quit what?" because obviously playing dumb would totally get the subject dropped rather than addressing his habit.

Not really, but Snake could dream. Frankly, quitting the drink was rough enough that he wasn't about to drop the cigarettes if he didn't have to, especially since he figured a bullet would probably get him long before lung cancer would. Didn't really pan out that way in the time line, but, well, this Snake didn't know that.