McAfee was a Staff Sergeant in the United States Air Force.
When the Stargate activated in the Embarkation room much to the shock of McAfee and the three guards who were there playing poker, they braced themselves for an invasion.
Airman Carol Weterings approached the wormhole and was captured by Teal'c of Chulak, the First Prime of the Goa'uld System Lord Apophis with Apophis himself and the other Serpent Guards coming through a few seconds later.
McAfee and the other guards demanded that Teal'c let Weterings go with both sides exchanging gunfire with each other. In the ensuring fight, McAfee and his colleagues who had been ill-equipped and poorly equipped to deal with such an assault were tragically killed by the Serpent Guards while Weterings was later captured. (SG1: "Children of the Gods")