Mackenzie had heard of the master of magnetism (who followed mutant rights and hadn't heard of Magneto?). She'd even been expecting that they would cross paths at some point. After all, chances were he'd know someone who needed legal defense. What Mackenzie hadn't been expecting was for Magneto of all people to wait for her outside her office.
Luckily, her expression remained neutral beyond a slight raise of her eyebrows. The cigarette she was smoking did wonders for keeping her calm as well.