A pizza run is , a case when your school is too far away from the local pizza place , and you gotta run and make good use of time because walking there will make you late for class. Usually there can be a race ,to see who gets to the pizza place first.
Dwight : Hey Chris , wanna go for a "Pizza Run" and get some meat curtains
Chris: Yeah buddy , rendez-vous
at the corner, let's do this.