TT #770 · Parashas Ki Seitzei · Seventh Aliyah · Passuk 25:12
then you shall cut off her hand; your eye shall not pity.
Torah Temimah points to Sifrei / Bava Kamma.
TT lemma: וְקַצֹּתָה אֶת כַּפָּהּ.
בַּמֶּה דְּבָרִים אֲמוּרִים? בְּשֶׁיְּכוֹלָה לְהַצִּיל עַל יְדֵי דָּבָר אַחֵר; אֲבָל אֵינָהּ יְכוֹלָה לְהַצִּיל עַל יְדֵי דָּבָר אַחֵר – נַעֲשֵׂית יָדָהּ כִּשְׁלִיחַ בֵּית דִּין וּפְטוּרָה.
English: In what case is this said? When she could have rescued by some other means; but if she could not rescue by any other means, her hand becomes like the agent of the court and she is exempt.
On the daf / in context: When the intervention is the only available means of rescue, the act is treated as justified.
Derash limiting liability when no alternative exists.
If the woman had no other way to save her husband, she is exempt from the penalty.