Walking away from a training bond without either paying it off or, at least, trying to negotiate a payment plan is certain death in the commercial aviation world. What you will do to one company you will quite probably do to another. A training bond is a simple contract that you have signed, walking away would be a breach of that contract and an employer could pursue you for settlement, that alone would incur considerable legal costs.
If you want out go and talk to your present employer. Work out a payment plan. Your new employer won't be very chuffed when/if they find out you broke a training bond and your present employer may just tell them! Chief pilots do talk to each other.
