Odds of Hanging On
Just don't do anything stupid. Most priests who lose their job have either been way out of line or have engaged in immoral AND illegal behavior. (In fact, it makes you wonder what the heck they thought they were doing getting into this business in the first place.)
Then there are also cases of firings due to a difference in beliefs. This priest who publicly supported gay marriage is just one of many examples of recent wrongful firings. Priests can often be trailblazers for radical thought because they do good for the sake of doing good, rather than glory. Unfortunately, they are sometimes persecuted for their actions and words.
If you're wanting to take a stance against the Catholic Church, be warned: You may lose your job. Don't let that be a reason to stop being a good person, though. Stick to what you believe in.