(coexisting on another dimensional plane)
McKenzie was a MACO assigned to the ISS Enterprise in 2155 and was one of several Enterprise crew members that left the starship in escape pods when the craft was trapped by Tholian ships in an energy field and destroyed. The surviving escape pods and their occupants, including McKenzie, were later retrieved by the USS Defiant, under orders from Commander Jonathan Archer, an officer who had led an assault team there from Enterprise.
Aboard the Defiant, McKenzie participated in a hunt for Slar, a member of the reptilian Gorn species. However, although several officers managed to corner the Gorn in a turboshaft, the creature was able to escape through an access tube. Simultaneously, all communication was lost with McKenzie and Brown, another member of the assault team that had been sent to find Slar.
Later, Major Malcolm Reed informed Archer of the incident on the vessel's bridge. (ENT: "In a Mirror, Darkly, Part II")