Thoughts on Bava Metzia 93b

1) The Mishna has listim, with a yud mem sofit. Rashi writes to fix the girsa as without the yud, because it speaks of a single robber:

הלסטם - גרסינן וחד לסטם קאמר:

After all, the gemara speaks of one (watchman) opposing the one listim. One need not change the girsa to say this, because whether malei or chaser, it can mean a single robber. Here is Jastrow, discussing it as the Greek listes  (see more here), with the mem sofit coming mistakenly in place of the samech.

2) There is an interesting pattern in the Mishna of a general rule about one, about two, and then a Tanna dividing even further between the two. Not exactly like a machria, but it feels similar in tone.

A) 

 זאב אחד אינו אונס שני זאבים אונס רבי יהודה אומר בשעת משלחת זאבים אף זאב אחד אונס

One wolf vs. two wolves. With Rabbi Yehuda elaborating (arguing? or while coming from the side, in a way even the Tanna Kamma would agree?). At a side wolves are common, they are emboldened.

B) 

שני כלבים אינו אונס ידוע הבבלי אומר משום רבי מאיר מרוח אחת אינו אונס משתי רוחות אונס

Two mere dogs. Strip out any opposing named Tanna, and the setup here is two mere dogs as opposed to two the wolves of the reisha. Rabbi Meir argues or elaborates that there are times, in a coordinated attack, that the shepherd cannot fend them off.

C)

הלסטים הרי זה אונס

If we look at the Tosefta, we see an elaboration. Firstly, that Tosefta uses ganav rather than listes. But it contrasts one ganav vs. two ganavim. With one, he can stand and oppose him. This is precisely the gemara's initial objection. It also clearly supports Rashi in claiming the Mishna speaks about only one.

In the Tosefta, it is Rabbi Yehuda again who elaborates / argues, and says that if it is an armed robber, even one.

This is exactly Rav's answer, in explaining the case of our Mishna. So the stam Mishna here is like Rabbi Yehuda, and endorsed by Rav.

3)

מי אמרינן אוקי גברא להדי גברא או דלמא האי מסר נפשיה והאי לא מסר נפשיה 

מסתברא דהאי מסר נפשיה והאי לא מסר נפשיה 

Some kitvei yad, and also in some Rabbinic writings quoting the gemara, have a teku in place of  מסתברא דהאי מסר נפשיה והאי לא מסר נפשיה .