Leaving in the Middle of a Bread Meal

I am a volunteer in the important organization Hatzalah, and often I have to leave for a call in the middle of a meal. When I return to the meal, do I need to recite the blessing again or not?

If before you left, you ate a kezayit of bread and you return within the time of satiation from your first eating, even when you are dining alone, since you are eating bread, and for bread, one must recite the final blessing specifically at the place of eating, it is considered that you have not removed your hand from your first eating, and there is no need to recite the blessing again, even for those who follow the opinion of the Shulchan Aruch due to the doubt in blessings. However, if when you return you are no longer satiated from your first eating, or if before you left you ate less than a kezayit, you need to recite the first blessing again when you return. And when you are on your way and you know it will take a long time until you return, it is preferable to recite the Birkat Hamazon in your place. Also, when you return, wash your hands without a blessing, and if you touched unclean places, wash your hands with a blessing.

Orach Chaim, Siman 178, Rema, Seif 2, Mishnah Berurah, there, Seif Katan 28 and Seif Katan 47