The McKenzie Airbase is a location in Syphon Filter 2. Essentially a military-run base for various aircraft and artillery in Colorado, The Agency under the guise of FEMA used it for smuggling Syphon Filter Virus infected Corpses in and out bypassing any security checks and customs.
The location is used for two missions, where Lian Xing escapes from the interior and later the exterior of the map.
After being apparently shot dead in Syphon Filter, Johnathan Phagan is brought to the air base, in fact still alive but comatose, for the ostensible purpose of draining his plasma for further research. Xing is also taken to McKenzie Airbase's infirmary for the same purpose. This medical facility is not directly under the purview of U.S. Military Medical Authority, but is administered by The Agency itself. She however manages to regain consciousness and assaults one of the doctors trying to drain her. Sneaking through the base, she watches as Elsa Weissenger and Dillon Morgan argue over Phagan's fate. The doctor wants to keep PHARCOM's CEO alive for research, but Morgan protests that he has to tie up loose ends, and switches off Phagan's life support to keep anybody from finding him alive. Lian regains her Combat Gear and gets help from an Unnamed Airman show allows her to escape to the exterior. From there, she confronts Thomas Holman, deals with one of the pilots for the F22 and eliminates Derek Falkan on her way out, stealing his chopper in the process.