Corrected entry: In the beginning when the wave hits the ship, Janeway's hair goes from being a curly up-do to being a mess after the wave hits to being back up in a plain up do when she enters engineering. She wouldn't have stopped to re-do her hair in the middle of the catastrophe.
Correction: She wouldn't have to stop to put her hair back up. My girlfriend frequently puts her hair up while walking or driving and doesn't lose any time at all.
Correction: She didn't stop to put her hair back. Just as she rounds the corner in the corridor before passing the doors to engineering she has her hands to her head, obviously fixing her hair as she walks.