Swift turns around, only to be mauled by zombies.
Swift was a S.O.G. special agent who served in only one mission. Before he was recruited for the Studies and Observations Group he was a US Marine. His father, grandfather, and great grandfather were all in a major war.
After presumably killing and destroying all zombies and evidence at Crisis, Alex Mason, Frank Woods, Joseph Bowman, and Jason Hudson return to the US. They are forced into the witness protection program to protect their identities and are forced to forever live at the Pentagon. All seemed well. However, during one rainy day in April, an urgent message is relayed to the Pentagon. The message requested immediate assistance, but the sender was unknown. The CIA tracked the signal to the coordinates, which led to an old Soviet experimentation laboratory in South America. Swift, Mason, Woods, and Bowman are organized into a task force and flown to the location. They parachute out of the plane. Almost instantly the four are attacked by zombies. During escape swim to the river boat, several zombies dragged Swift under. The river boat was forced to leave without him, due to the overwhelming amount of zombies attempting the climb aboard. What became of Swift afterwords is unknown, but it's most likely he drowned.