Swift is a SOG member, but wields an AK-47 instead of a Commando. This is similar to Tvelin from Project Nova, as both respective characters wield weapons potentially taken from the opposing factions; Swift with his AK and Tvelin with an STG-44.
Coincidentally, both characters are scripted to die regardless of the player's actions.
If the player tries to sprint at Swift before he dies, he says "Back the fuck up", done to prevent the player from getting past Swift and saving him.
On the Wii version, however, the player can easily get past Swift. They will see that the Vietcong is not standing there. However, he has spawned, as the player can see his hand sticking out of the cave wall. When the trigger is activated, the Vietcong will dash through the cave wall and stab Swift.
If the player were to shoot the Vietcong before he stabs Swift, he oddly randomly dies even though the knife didn't touch his neck.
Swift seems to spawn right after the player passes the last hut right before the rat tunnel on "Victor Charlie".
After Mason sees Reznov in the rat tunnel and speaks to him, Swift says "What the fuck is wrong with you? You need to get your shit together, now.", indicating that Mason is hallucinating Reznov's presence.