Implied question: Why does it say that he stepped, and it does not say that he touched?

Answer: This is because our Mishnah discusses [a Kusi's] Tachton.

Implied question: We should establish it when he did not immerse, and something interrupts between the Chaver's garment and the Kusi's foot!

Answer: You are forced to establish it when he immersed, in order that it will be a Sefek-Sefeka. If he did not immerse, what is the difference whether he had Bi'ah recently or a long time ago? (Surely, at one time he was Bo'el Nidah!)

Support - Citation (Taharos 7:6 - Mishnah): If thieves entered a house, only the place where they walked is Tamei;

Citation (cont.): What are they Metamei? They are Metamei only food and drink and open Klei Cheres, but Mishkav, Moshav and Klei Cheres surrounded by a Tzamid Pasil (tight seal) are Tehorim;

If there is a Nochri or woman with them, everything is Tamei.

Inference: An Am ha'Aretz does not make a Mishkav or Moshav [and Av ha'Tum'ah], and he is not Metamei through moving.

Implied question: It was taught there (8:1) that if one lives with an Am ha'Aretz in a Chatzer, and he forgot Kelim in the Chatzer, even barrels surrounded by a Tzamid Pasil, they are Tamei!

Answer: They are Tamei due to his [the Am ha'Aretz'] wife.

Implied question: A Tosefta in Chagigah (3:21) teaches that Safek Reshus Am ha'Aretz, his Midras and Heset are Tehorim for Chulin and Tamei for Terumah;

Answer: Also this is due to concern for Ishto Nidah. Also the Mishnah in Taharos (8:1, says that barrels surrounded by a Tzamid Pasil are Tamei) refers to Terumah.

Question: Why are Bigdei Am ha'Aretz Midras also for Perushim (who are stringent about Taharah)?

Answer: We are concerned lest Ishto Nidah sat on them.

Opinion #2 (R. Moshe of Pontaiz): We did not make an Am ha'Aretz like a Zav in any way. He is Metamei only due to his clothes, which [perhaps] Ishto Nidah sat on them, and he carries a Midras;

His spit is Tamei because it touched his lips, and not due to Mayan (one of his bodily fluids).

Rejection #1: If so, above why did we say "Tum'as Am ha'Aretz does not apply, for he immersed"? You are forced to say that he is naked, like I explained above;

Even if he did not immerse, he is not Metamei, since he separated (is not wearing) the Midras, like it teaches in Toras Kohanim that I brought above (33b DH b'Kusi);

Rejection #2: Regarding a Tzeduki, here we ask "in any case, [it is Tamei due to spit of an Am ha'Aretz]!" I.e. how did it help to ask his wife?

(According to R. Moshe, it helped greatly!) If he (the Tzeduki) was a Bo'el Nidah, he (the Kohen Gadol) and his garments became Tamei, like one who carries a Zav's spit;

If [the only concern is] for spit of an Am ha'Aretz, only his garment became Tamei, because a liquid is Metamei a Kli mid'Rabanan.

Implied question: Dam [Tohar] of a Yoledes who did not immerse is Tahor mid'Oraisa, and Beis Shamai say that it is Tamei only wet, but not dry!

Answer: There, people know that since Yemei Leidah passed, her blood is not Tamei mid'Oraisa;

However, a Nochris, whom they made like a Nidah, for they (Nochrim) are like Zavim, if we will distinguish in her blood [between wet and dry], people will come to distinguish regarding a Yisraelis' blood.

Implied question: Why is Dam Tohar of a Metzora'as totally Tahor?

Answer: We are not concerned that they [Rabanan] were not stringent about her, since she already immersed, and the blood is Tahor.

Question: Why don't we burn due to it? We burn due to a Safek about spit of an Am ha'Aretz, in Shabbos (15b). All the more so [we should burn] due to a Nochri's Zov!

Answer: We burn due to an Am ha'Aretz's spit, for there is concern for Tum'ah mid'Oraisa if he is a Zav or Bo'el Nidah;

A Nochri has no Tum'ah mid'Oraisa.

Observation: In Shabbos (86b), the Gemara fixed this (limitation, that he asks only about after three days) in Rav Papa's words.

Explanation #1: Rav Papa himself did not say this, like it connotes here. (Rather, the Gemara itself resolved that surely, within three days it is Tamei.)

Support: We find like this in Bava Metzi'a (112a). They asked Rav Sheshes whether or not Bal Talin (the Isur not to pay a worker the same day) applies to a Kablan;

Citation (112a): Does a craftsman acquire improvements he made to a Kli, and [when he gave the Kli to the one who hired him, the money owed to him] is a loan? Or, he does not acquire, and [the money owed to him is] wages?

Citation (cont.) Answer (Rav Sheshes): He transgresses.

In Bava Kama (99a), we establish the question to discuss a Shali'ach to deliver a letter. A craftsman acquiring improvements does not apply! (This shows that the questioner never said "does a craftsman acquire...? This was the Gemara's elucidation of the question, and it is clear from 99a that the Gemara misunderstood the question!)

Explanation #2: Rav Papa said all this. Here, the questioner thought that Rav Papa asked about both within three days and after three days;

Do we say that since [Nochrim] eat vermin [they are hot, so] even within three days [the semen] putrefies, and it is Tahor?

Or, perhaps since they do not worry about Mitzvos, [they are cool, so] even after three days [the semen does not putrefy, and] it is Tamei? (After this, we answer that Rav Papa asked only about after three days.)

Question: We should establish it to teach about blood of his wound, or that comes from his mouth or nostrils, and other fluids in him that are not a Mayan;

Regarding a Zav, we are Metaher them below (55b)!

Answer: We do not want to establish it regarding these, for we do not find that these are Tamei in any place;

However, Dam Tohar is like Dam Nidah, even according to the opinion that they come from two different sources [in her body].

Implied question: We could have said [that they learn from] "Ish Ish [Ki Yihyeh Zav...]"!

Answer: We want to establish Beis Hillel even according to the opinion that holds that the Torah speaks like people speak. (This opinion does not expound the doubled word.)

Question: Below (56a), it connotes that Zov is not a Mayan, for it says "we should learn from his Zov, which does not gather [before it leaves]!"

Answer #1: There, it says that we should learn from his Zov, if it is not a Mayan.

Answer #2: Even though it does not gather, like it says there, in any case we ask here whether it is like a Mayan, and we include it in a Metzora from the verse "la'Zachar", like other Mayanos;

This [Hava Amina] is because in a Zav, Zov has severe Tum'ah, just like his spit and urine.

Question: Did Rava not know the Seifa of the Beraisa taught below (55a), which explicitly says that Se'ir ha'Mishtale'ach Yochi'ach (proves that something can make others Tamei even if it is Tahor)?!