Pesachim 3:8-4:1

Pesachim 3:8

If a person started leaving Jerusalem and he realized that he had sacrificial meat (that cannot be brought outside the city) in his possession, then if he has passed Tzofim (from where the Temple could still be seen), he burns it where he is. If he has not yet passed Tzofim, he goes back and burns the meat with the wood of the Temple woodpile. Rabbi Meir says that one must return for chometz (in mishna 3:7) and for sacrificial meat in the volume of an egg; Rabbi Yehuda says in the volume of an olive; the Sages say one must return for sacrificial meat in the volume of an olive and for chometz in the volume of an egg.

Pesachim 4:1

In a place where the accepted practice is to work on the day before Passover until midday, one may do so; in a place where such is not the accepted practice, one may not do so. If one goes from a place where the practice is one way to a place where the practice is the other, he must act according to the stringencies of both places. One may not change because that leads to conflict.