Whenever you're working for someone, your actions and how you conduct yourself reflect upon your employer. Their reputation is your reputation. Mess up, and you mess them up.
This is especially true in the film business. If you're lucky enough to work for a heavy hitter or someone doing something cool, you must absorb everything you can about their strategies for success. But you must also make sure that everything you do, makes their lives easier.
If you make a mistake, and you will, fess up and move forward.