Other authorities allow a firstborn to break his fast under such circumstances (Minchas Yitzchak 9:45; Teshuvos V'hanhagos 1:300, 2:210 in the name of Rabbi Yaakov Yisrael Kanievsky).
Moishe Finkel | Moishe Rosen | Moishe Sternbuch | Moishe's Bagel | Moishe "Maurice" Finkel |