Hand Over One or You'll All Die

(1) Now there happened to be there a certain base man, whose name was Sheva, the son of Bichri, a Benjamite; and he blew the shofar, and said, ‘We have no portion in David, and we have no inheritance in the son of Jesse; every man to his tents, O Israel.’ (2) So all the men of Israel went up from following David, and followed Sheva the son of Bichri; but the men of Judah clung to their king, from the Jordan to Jerusalem.

(15) And they came and besieged him in Abel of Beth-maacah, and they poured a ramp until it stood even with the outer wall; and all the people that were with Yoav battered the wall, to throw it down. (16) A wise woman called out from the city: "Listen! Listen! Please say to Yoav, 'Come close to here so that I may speak to you.’" (17) So he drew close to her; and the woman said: "Are you Yoav?" And he answered, "I am." Then she said to him, "Hear the words of your maidservant." And he replied, "I am listening." (18) Then she spoke, saying, "[Your men] should have spoken at the start saying, 'Let them inquire at Abel [about surrender],' for they would have made peace. (19) I represent the loyal faithful people of Israel. You are seeking to destroy a city in Israel? Why will you swallow up the heritage of the Lord?’ (20) And Yoav answered and said: ‘Far be it, far be it from me, that I should swallow up or destroy. (21) The matter is not so. Rather, a man of the Mount Ephraim, Sheva the son of Bichri by name, has lifted up his hand against the king, against David; deliver him olone, and I will depart from the city.’ And the woman said unto Yoav: ‘Behold, his head shall be thrown to you over the wall.’ (22) Then the woman went unto all the people in her wisdom. And they cut off the head of Sheva the son of Bichri, and threw it out to Yoav. And he blew the shofar, and they were dispersed from the city, every man to his tent. And Yoav returned to Jerusalem unto the king.

It was taught: If a group of people were traveling and they chanced upon a marauding army which demands of them, "Hand over one of your group, or we will kill all of you," you may not hand anyone over, even though all will end up being killed. If however they specify an individual, you may hand him over, as was the case of Sheva the son of Bichri. Rabbi Shimon ben Laskish says that the case of Sheva the son of Bichri was different since he was liable for the the death penalty. Rabbi Yochanan says that even had he not been liable for the death penalty, [he could have been handed over].

These were the sons of the Galileans about whom a rumour spread that they killed a person. They came before R' Tarfon and said to him: "The master should hide us[from the authorities]" He said to them "What should I do"? If I don't hide you [the authorities] will see you [and execute you, on the other hand], should I hide you? I would be acting contrary to the rabbis who said "you should not accept Lashon Hara, but you should take note of it" and if I do listen to the rumors, it is forbidden for me to hide people guilty of murder. You go hide yourselves.

The reason R. Tarfon was unwilling to hide them is not because he believed it was forbidden to hide people guilty of murder. It was because if he hid them, he'd be putting his own life in danger

It says in a number of places that the "martyrs of Lod, no one can touch their portion in Gan Eden" What did they do? They were killed because a daughter of the king was found killed, and they said "the jews killed her" and decreed death to the Jews, and these two stood up and said "we killed her" and the king killed only them