Service men and women in Egypt, along with presumably their guide, in front of the Great Pyramid, likely taken during Mazer's journey to the CBI. During WWII.
It is quite possible that Mazer deployed overseas as a replacement aboard ATC transport aircraft, not knowing to what unit/plane he would be assigned until his arrival in India or China. If so, this eclectic group might even be a sampling of the people on a recent group flight.
(Thanks to Tony Strotman for additional information.)