It is first seen in the hands of a guard who is sent to kill Dana Polk and Marty Mikalski. Marty then takes the Beretta and shoots a mutant with it. He later hands it over to Dana. The Director also tries to fire the pistol. One of the workers is seen committing suicide with a Px4, and a uniformed security guard uses one to defend herself from a Clown(albeit to no effect). Daniel Truman also pulls out a Px4 when The Scarecrow Folk break in to the lab.