There's a saying among pilots, at least so I've been told by some of my instructors, when you are really in a pickle and can't think of a way to make your situation better, you are "out of altitude, airspeed, and ideas." In other words, you are going to crash soon and there is nothing you can do about it.
One of the important things that ukemi (the practice of taking falls as someone else practices techniques) teaches you is to stop putting energy into the situation when you are out of altitude, airspeed, and ideas. That extra energy is not only unhelpful, but you're going to have to eat it during the impact. When you get yourself into a situation where your skills and efforts are not going to help you change the outcome, relax and crash with as much grace as possible.
Surely you've noticed that as you spend more time in a martial art like aikido or judo, you can be thrown more vigorously and can survive more outrageous techniques. We usually attribute this to increased skill at falling, but this is also due in part to increasing awareness of one's own limits and skills. As you gain a better understanding of where your edge lies, you are better able to know when to fight and when to lie down.