To need an exit strategy applies to using the bathroom, but only after consuming large quantities of food. In some cases, the term "Exit strategy" can be used in an act of foresight, such as dining at a buffet or, possibly, Taco Bell.
Brett: Hey man, wanna play some Capture the Flag?
Steve: Gimme 10 minutes dude, I just got back from China Buffet and I need an exit strategy.
Brett: That's gross!