SPOILER ALERT
August 24, 2010
Wearing a hazmat suit, Sierra explores a seemingly abandoned military camp. At first, she sees only corpses, until she spots a girl hiding. The young woman is Gaby, injured in the foot and searching for her boyfriend Colton, who had assured her that in this camp there was a hidden tunnel leading to Mexico.
The two women eventually find Colton, who guides them toward the tunnel but then tries to get rid of them both. Together, Sierra and Gaby manage to kill him and reach the tunnel’s exit, free to head toward Mexico.
P.S.: The dates in the timeline are approximate, but everything happened more or less around those days.