If the operation is actually unsafe, report it. Don't just bog off and wait to read about a crash in the newspapers. If the company is out of business or grounded for safety reasons then your bond can't be enforced and you're on your way to being a free man (unless you're bonded to a crewing agency).
If you're entering into the bond with the view that you might have to break it then you're entering into a contract in bad faith, no matter how noble your reasons may appear to you. The other option, mentioned by other people, is to negotiate to buy your way out of your bond.
Seriously, if you lent someone a five figure sum and they declined to pay in back on the grounds that it had become inconvenient and they thought you probably wouldn't be able to sue them, what would you think of that guy?