There are days when most rules are suspended in the face of danger. Today isn’t one of them. In today’s daf, the assumption is that those sent to perform a mitzvah are not harmed, although there is a question of whether those returning from performing a mitzvah are also protected.
Daf 331 (Pesachim 8a-8b)
The gemara explores the question of why we use a candle to search for chametz. There is poetry in this: “A man’s soul is the candle of Hashem, which searches all the chambers of one’s innards.”
What places do not have to be searched for chametz? The gemara considers various cracks, holes, partitions, and storage facilities; judging some as requiring searching. Must one search in a ruin? Some say no because of the danger, but R’Elazar says “Those sent to perform a mitzvah are not harmed.” Nevertheless, Rav Ashi worries that one may become distracted and be harmed during an interval when he is not performing the mitzvah. Rav Nachman bar Yitzchak suggests that the danger in question is not from the instability of the ruin, but from gentiles. Pleimo says it is the danger of witchcraft. Rav seems certain that going to perform a mitzvah is protected but is not certain that the protection remains in force when one is returning home after performing the mitzvah.
The rabbis debate which two rows of a wine cellar must be searched– is it the outer ones, the upper ones, etc.?