L I double R: where to sit?

Here's my situation on the train the other day:
It was no surprise that my car would be relatively full as it was rush hour / peak time. Having just made it onto the train as the dings were going off and the door began to slide, I was not expecting to get a comfortable seat if even any at all. I noticed some vacant spots scattered around the car but was feeling very vulnerable. The seats were only 'In-betweens' whereby a 3 seat bench was occupied at both ends, and 'up-against-the-wall-next-to-a-sleeping-fat-guy' where by I'd be smudged up against the wall next to a fat guy.
Now at first glance the answer seems simple: wake up the sleeping fat guy, generate a mean stare-down from him, have him get up in a very grumpy manner, slide up against the wall with bag in hand (as this guy expects that since you actually had the audacity to wake him up and make him stand, he'll be getting more room than you because 1. he was there first 2. you woke him up) and take up as little room as possible. [Worrying about having to wake him up for a second time is another possible scenario. It stinks when you have to switch at Jamaica and he's going all the way to Ronkonkoma even though nobody lives in Ronkonkoma.]
On the other hand, it's kind of tempting to sit in between 2 people. The question is whether the 'urinal-rule' comes into effect or not. There is an unofficial rule of proper etiquette when there are 2 guys occupying the ends of a 3 set urinal. The rule is YOU CAN'T STEP UP TO THE MIDDLE ONE IF THERE ARE NO DIVIDERS. Now do we apply the same logic to the scenario at hand? On one hand the reasoning is not the same as the urinal rule. On the other hand- this can be an almost 30 minute endeavor depending on the destination(s) of all 3 guys. 30 seconds and 30 minutes can stimulate different emotions.

Anyway, in case you're wondering what I did that day I'll tell you: I stood for 25 minutes. Next time I'll be prepared though.

LIdoubleRed