The Mishna in Brachos (30b) says that one may not interrupt tefilah (i.e. shmoneh esrei) even if a snake winds itself around one's foot. The Bartenua explains (based on the gemara 33a) that the law in the Mishna applies specifically to snakes because most of the time (rov) snakes do not bite. However, if a scorpion were to attack one can interrupt tefilah because scorpions usually do bite with fatal consequences.
Question: There is a principle in halacha of ain holchin b'pikuach nefesh achar harov, meaning that when it comes to questions of life and death we do not play odds but consider even the smallest chance of saving life worthy of effort. For example, if an avalanche buries someone on Shabbos, even if the odds are that the person in dead or not even Jewish, we must desecrate Shabbos to dig the person out based on the small chance that a Jewish person may be buried under the rubble and still alive. If so, why do we rely on the fact that most (rov) snakes do not bite and prohibit an interruption of tefilah -- if even only a small percentage of snakes do pose a danger, shouldn't we invoke this principle of ain holchin b'pikuach nefesh achar harov???
This question is tangentially related to the topic of yesterday's post -- it is discussed by R' Elchanan in his essay about secular studies in the context of the protection afforded by mitzvos, but multiple answers (I think) are possible. I'll give time to think it over and comment before posting answers.