Notice Jesus asks the Pharisees if it was lawful on the Sabbath to save a life. So, can you break God's law to save your life if it came to that?
Playing Devil's Advocate I disagree. Jesus objected to the way the Pharisees interpreted the law regarding the sabbath but he never argued that it was okay to break the law. He observed the Law meticulously and taught this followers to be even more observant than the Pharisees.
His argument was not that it was okay to break the sabbath by healing or saving a life but that doing these things was not breaking the Law.
Similarly the key point about blood transfusions is not that it is okay to break god's law to save your life but that blood transfusions are not against any law...