Ethics: My new employee refuses to do some parts of her job. Should I fire her?

Terminating her would be legal. Is it the right choice?

A reader writes: I have a new employee who is refusing to do some parts of her job. She hasn’t done this with me directly, but when I left for a week’s vacation, I gave very clear guidance on what she should be working on. That included learning to use some of our equipment, practicing her job skills, and reviewing training videos with the team.