To recap, in Episode 7, "Red in the Face," arrogant young (oh wait, all the men in the show are arrogant and young...except the ones who are arrogant and old) Pete exchanges the garish Chip 'n' Dip tray he'd gotten as a wedding present for a 22-caliber rifle*. To the vast amusement of the guys crowded into his office, he takes aim at "the girls" in the secretarial pool and pretends to pop each one off. Despite his wife's resulting fury (or maybe because of it), Pete doesn't return the rifle and it remains propped against a wall in his office. It's the sole background object during his clinch with secretary Peggy.
To mix metaphors, that rifle is a ticking bomb. According to the immutable laws of drama, as laid out by Anton Chekhov (courtesy of Wikipedia):
- "One must not put a loaded rifle on the stage if no one is thinking of firing it."
- "If in the first act you have hung a pistol on the wall, then in the following one it should be fired. Otherwise don't put it there."
*You could buy a rifle in NYC in 1960? And blithely parade with it through the streets and into an office building?? Really???