On the Orion, Tegan Brown is the Chief Security Officer. Her presence on an away team is an advantage in combat situations. She is skilled with the plasma rifle and by necessity is proficient in unarmed combat as well.
Tegan was assigned by her request just before the Orion mission began. During the exploration phase of the mission she didn’t get out of her quarters very much and only made a few friends among the crew, one of them being Erica Reed.