When you have tried everything within reason to solve your problems, what does that mean? What exactly is "reasonable"? Does it mean that you have tried every single thing that you are physically capable of? Does it mean that you tried every plan that you came up with? Does it mean you've tested out your ideas but couldn't find any that showed enough promise? Does it mean you tried your best plan, but it failed, so you resigned yourself?
What is reasonable is obviously relative. So what your characters think is reasonable should also be relative.Not only is one's definition of 'reasonable' relative, but the degree that somebody is comfortable with doing something they find unreasonable is also relative.