A little past 1 in the morning, a car pulls up and stops right beside the fence. The security guard on duty flicks away his cigarette and prepares for a possible confrontation but then visibly relaxes when the security guard you saw at the end of your shift exits the car.
He ducks through the fence and slaps the guard on duty on the back. He keeps his arm on his shoulder and pulls him so he is facing away from the hole in the fence while they talk. He slips him a hand rolled cigarette which the uniformed guard gladly accepts. This provides enough distraction to allow two men in dark clothing to slip through the hole in the fence and slide into the shadows unnoticed by everyone but you.
The shady guard looks over his shoulder and sees that all is clear. He gives the guard on a duty a handshake and heads back to his car. He suddenly stops and snaps his fingers. He makes a very overexaggerated charade of someone forgetting they needed to take care of something. You seem him explaining this to the guard on duty who nods along and waves him off. The man walks back toward security HQ. As soon as he is out of sight of the guard on duty, the shady guard takes a detour behind some storage crates. No doubt he is working his way back around to meet up with the two that snuck inside.
The two men that snuck in are about 100 feet away. You see their shadows occasionally as they quickly move between containers. You have a general idea of where they are, but it is not yet clear where they are heading.