Continuity mistake: When Margaret got off the elevator, she had hair from her right side pulled back over her head and curved toward the left side. It stayed like this while she was walking down the hallway, but her hair was different when the camera shifted to a front view. (Her hair frequently changes from combed to dishevelled or between various forms of dishevelled - too many to document here and without adding anything more of significance). (00:12:35 - 00:14:11)
Continuity mistake: On the train, Margaret's hair had a distinct uneven, broken part (the middle section running parallel to the first and third lines), but her part was linear when she got to work. Also, in the hallway, some hair was raised near the back of her head in front views but not in rear views. (00:04:15 - 00:04:40)