Remote chance? Sure is. I've seen it happen too many times. A number of times, when you break out balls, you won't have a shot on anything! It may not be high odds, but it does happen.
The way I see it, while I do feel the draw back off the 12 is very possible, I also believe that most people can not get that kind of draw. And, if you do get the breakout from there, there is a very good chance that you won't be able to even see the 8. You do have to make a very good shot, and get a little lucky on it.
Now, if you take off the twelve now, and don't get the breakout, he has to screw up REALLY bad for you to win. With the 12 still on the table, the chances are raised somewhat in your favor of having a chance to win. You are still the favorite to lose this game, but I like increasing my chances when I can. I don't believe taking the 12 out now does that. Trying to bank it cross corner for the breakout, while possible, I think is very low odds. I agree that the double kiss is very large on that shot.
Any way you look at it, you are in a pickle here, and a few things have to go your way to win this one.
edit: O.k. Jude, assume you go for the breakout now, but you miss the breakout. What are you going to do now? Now, all you have is the 8 on the table. It is not makeable anywhere right now. Even you just skimming it, you rearrange the 3-5-8 to where he probably will now have a runout opportunity. If you move that 5 to where it is makeable in either corner, you are done for.