Mishna Sanhedrin 8.6
[A thief] who comes through a tunnel [into one's house] is judged on the basis of his end. If he came through a tunnel and broke a jug: if he has blood-guilt, he is liable; if he does not have blood-guilt, he is exempt.
Rambam comment
- הבא במחתרת נדון על שם סופו היה בא כו': וכן הבא במחתרת ידוע הוא שכונתו שאם יעמוד בעל הבית להציל ממונו מידו שיהרגנו This ganav is judged because of the supposed course of the events. It's known that if the owner resists to him and doesn't want to give his money, he will kill him.....
The source is the verse Exodus 22.1
אִם־בַּמַּחְתֶּ֛רֶת יִמָּצֵ֥א הַגַּנָּ֖ב וְהֻכָּ֣ה וָמֵ֑ת אֵ֥ין ל֖וֹ דָּמִֽים׃
If the thief is seized while tunneling, and he is beaten to death, there is no bloodguilt in his case.
Rambam explains that this case is only an example, Tora uses common language, corresponding to most cases. Since the thief is punishable by death, that is instantaneous death because he is included in the din of rodef (the next Mishna), he needs not to pay for damages made during his action. The rule is that one is killed doesn't pay because Torah addresses the great punishment only.
These may be saved [from transgression] with their lives [i.e. by killing them]: one who pursues his fellow to kill him,