Commentary for Avodah Zarah 140:13

Rava again demonstrates his ability to explain away suspicious circumstances with regard to wine. Although it very much looks like the girl touched the wine, we are allowed to assume that she only touched the froth on the outside of the jug.

Elazar allowed the casks of wine, but R. Dimi is not sure why. It could be that he holds that this is a case where we are not sure if he entered an area with impurity in it (below the Talmud will raise a difficulty on this) or it could be that the majority of the soldiers were Jewish (this seems unlikely to me).

The story does not seem to be like a case where it is uncertain whether they entered a certain area. Rather it is like a case where we know they entered a certain area that had an impure thing there but we just do not know whether they touched the impure thing. After all, we know they opened many casks of wine. Thus even R. Eliezer should be stringent in such a case.
The answer is that there is in essence another uncertainty in play here. Since they opened so many casks, it could be that they were looking for money and not looking for drink. Therefore, this is like a case of uncertainty about whether he even entered and R. Eliezer would indeed rule leniently.

We do not need to assume that the Jewish woman gave her the key so that she could enter the room. She may have been given the key just to watch the key, not so that she can enter the store.

Abaye cites a baraita to prove the above ruling. The baraita says that we can assume that the am ha’aretz was entrusted only with the key and will not go in and defile all of the pure things. All the more so we can make this assumption about yayin nesekh whose rules are assumed here to be more lenient.

The Talmud confirms that the laws of purity are more stringent than those governing yayin nesekh. The halakhah here refers to a case where a courtyard was divided with a low partition and a haver, one who strictly maintains the laws of ritual purity, lives on one side and an am ha’aretz, who does not maintain his own purity, lives on the other. According to Rav we must assume that the am ha’aretz touched the pure things belonging to the haver and defiled them. But if a non-Jew is living on the other side, we need not assume that he touched the wine and caused it to be nesekh.

The baraita refers to a case where there is an inner and outer courtyard, the inner one belonging to a haver and the outer one belonging to the am ha’aretz. Although the am ha’aretz could stretch out his hand and touch the haver’s belongings, we do not have to assume that he did so. The haver’s stuff remains pure. This seems to contradict Rav.
Rav answers that this refers to a case where the am ha’aretz will fear getting caught—looking like a thief. Thus he will be deterred from touching the haver’s pure things. But if he has no such fear, the pure things would have to be considered defiled.

This time the difficulty is against R. Yohanan. This baraita proves that if the am ha’aretz can reach the haver’s stuff, we must consider it impure.
Yohanan could answer that in this case the am ha’aretz could have an excuse—he was only stretching his hand.

This baraita clearly disagrees with Rav and holds that even if the am ha’aretz could reach there, the haver’s things remain pure.
Rav admits that he does not agree with this baraita. He holds like R. Shimon b. Gamaliel, whose opinion we saw above. Amoraim cannot hold opinions that disagree with all tannaim, but if there is disagreement among the tannaim, they can hold like whichever opinion they want, although there is still a preference for the majority opinion.

If the marauders enter the city in a time of peace, the assumption is that they may make libations from wine in open casks. Nevertheless, wine that is found afterwards in closed casks is permitted. The mishnah is not assuming that the marauders will not open the closed casks. After all, we have seen over and over in the previous mishnayoth that we must suspect that the non-Jews will open the casks and take from the wine. Rather the reason that the wine is permitted is that if the marauders had opened the casks they would not bother to reseal them. Unlike the non-Jews in the previous mishnah who might have attempted to be sneaky and take a drink without getting caught, the marauders have no such concern.
However, if the marauders entered the city in a time of war, all of the wine is permitted, since they are too busy making war to offer libations.