Question 082: Firearm defense

Do you think putting a finger or thumb between the hammer and cylinder of a revolver (when ready to fire) would break ones finger if the trigger were pulled? I have heard of people having to cut their own throats to breath after choking on something. Where would one want to make the incision? I ask this because I almost choked on steak the other day and realized that I should probably find this out.. just in case.. (I've tried to look this up. It's one of those things that's very hard to find because of the wording).