On Shabbat, when in fear of being hurt by a creature, if one cannot trap it, why does one have to kill it lefi tumo (inconspicuously), if the determining factor is to kill to defend?
Is it only when one kills for the carcass that involves a deorayta?
How about if one kills for fun, notwithstanding the fact that this may involve Baal tashchit etc?
Answer:
Killing for fun remains derabanan, and it is only a Torah prohibition when one wants the carcass for some purpose or other.
Although it is permitted to kill in self-defense (and for reasons of potential danger), the Sages nonetheless enacted that where there is no immediate danger (the species is not deadly, and it is not chasing the victim) the killing should be done inconspicuously, to distance the act further from the Torah prohibition.
