"Cyberdyne security guard #2" was a security guard in the Cyberdyne building.
Terminator Genisys timeline
After witnessing a copter crash land in front of the Cyberdyne Systems building, he was told by another guard to call the authorities on the building's landline phone. As the guard made the call, he suddenly stalled on the call when he saw John Connor suddenly emerge through the front door. He was then suddenly fatally impaled by the T-3000's metallic liquid metal capabilities which spawned from one of it's arms. The T-3000 then proceeded to impersonated this guard's voice as it told the authorities that everything was under control.