Why salvation is attained through faith, not good deeds?

In Christian theology, salvation is attained through faith, not good deeds. There are a lot of explanations. All make me more confused. Then I realize the real explanation.

What your boss wants? He wants your obedience. He demands your faith to him. Your boss doesn’t necessarily want you to do good deeds. This might undermine his authority. 

Faith to your boss, or your god, is the only path to salvation, or good relation with your boss. 

These several days, there are a lot of news about a school teacher in China who got killed in 2003.  He got killed because he exposed the corruption in his school. He did good deeds. That undermined authority of the authority. He had to be destroyed. His family tried to get the government to catch the murderers. But the authority protects the authority. 

Many years later, one murderer was arrested on different charges. He must have offended some more powerful guys. He confessed his 2003 killing. That is when we learned about the old story. 

Good deeds cannot lead you to heaven. They will lead you to hell. Only faith to the power (god, government) leads you to salvation and heaven.