My best friend ask my sensei this same question and he said "It really just depends on the scenario. Are you up against a wall? If so, stay calm, if he wants your money give it to him. You can always get more money, you only get one life. If he doesn't want money and instead wants your life try to disarm as best you can." To this my friend said, "And if your not against a wall." Sensei said, "Duck and run in zig-zag patterns."