• ואלו הן שמצילין אותן בנפשן: killing a רודף

The next Mishnah states: ואלו הן שמצילין אותן בנפשן – these are those whom we save from sinning with their lives (i.e., they are killed to be stopped): one who is pursuing someone to kill him, or pursuing a male, or a נערה המאורסה, to have relations with them. However, one who is pursuing an animal for relations, or is about to be מחלל Shabbos or worship avodah zarah, is not killed. Rashi explains that this law applies where there is an עבירה, and "פגם" – there is disgrace to the victim (or death).

The law to kill a potential murderer is derived from a hekesh from נערה המאורסה, where the passuk says: ואין מושיע לה – there was no rescuer for her, which implies that if there was a potential rescuer, בכל דבר שיכול להושיע – he must save her in any way that he can save her, including killing the pursuer. A Baraisa expands this to include someone pursuing any ערוה (punishable by kares or מיתת בית דין), and excludes relations of חייבי לאוין. Rebbe Shimon ben Yochai holds one is killed even to prevent him from serving avodah zarah, and Rebbe Elazar bar Rebbe Shimon applies it even to one attempting to be מחלל Shabbos.

• Killing a pursuer where the victim cries out to leave him

In the Baraisa, Rebbe Yehudah said: אף האומרת הניחו לו שלא יהרגנה – even if [the woman] tells rescuers, “Leave him to violate me and do not stop him,” so he will not kill her (if they attempt a rescue), the pursuer cannot be killed. Rav Pappa defines the machlokes: במקפדת על פיגמה – when she is concerned about her being disgraced, ומניחתו שלא יהרגנה – but she allows him to violate her so he will not kill her. The Rabbonon hold: אפיגמה קפיד רחמנא – the Merciful One is concerned with her disgrace against her will, and here, where she objects to being violated, and only allows it to protect her life, the pursuer may be killed (however, if she consents to be disgraced, he cannot be killed). Rebbe Yehudah holds that the Torah allowed killing a pursuer משום דמסרה נפשה לקטלא – because she might sacrifice herself to be killed rather than be violated. Here, where she clearly will not sacrifice herself, the pursuer is not killed.

The Gemara clarifies that the Rabbonon hold a pursuer is only killed to prevent פיגמה רבה – her great disgrace (i.e., an ערוה, whose relations render her a זונה), not the lesser disgrace of an אלמנה being violated by a Kohen Gadol (who is only rendered a חללה).

• How one who violates an ערוה can be liable for קנס if he could have been killed

The Baraisa above taught that one pursuing any ערוה can be killed to stop him. The Gemara asks that a Mishnah teaches that one who violates his sister pays the fifty-shekel קנס for violating a בתולה. But if he could have been killed at the time, he should be exempt from the קנס, because of קים ליה בדרבה מיניה!? Some suggested that she becomes disgraced at the moment of העראה (the first stage of relations), after which he cannot be killed, and the קנס obligation takes effect when he makes her a בעולה. However, this answer is untenable according to the opinion that העראה is when she becomes a בעולה. Rav Chisda answers that the case is where he first had relations with her שלא כדרכה – unnaturally (so she is already disgraced, but still a בתולה), and then violated her normally, for which he becomes liable for the קנס. Rava says the case is where she tells rescuers to allow the pursuer to violate her, following Rebbe Yehudah’s opinion that the pursuer cannot be killed. Rav Pappa says the case is במפותה – where she was seduced, not forced, and all agree the man cannot be killed. Abaye offers an additional answer.