Berakhot Daf 22

Unfortunately, the last few minutes of the shiur did not record, mainly because the Ipod's battery failed...I plan to replace it today so that we won't encounter the problem in the future. For a summary of the last few points of the Gemara that are omitted, borrowed from here:

(g) One of the following teachings was taught by R. Yochanan or Reish Lakish, the other was R. Elazar or R. Yosi b'Rebbi Chanina.
(h) (Chacham A): The first Tana distinguishes between learning himself and teaching others -- this is only for Choleh ha'Margil, but nine Kabim always suffice for Choleh b'Ones, even if he plans to teach others;
(i) (Chacham B): In every case, 40 Se'ah are required if one plans to teach Torah to others.
(j) (Chachamim C and D are from the same pairs as above.)
(k) (Chacham C): R. Yehudah requires 40 Se'ah (an actual miqveh) in any case -- the water must be in the ground, not in a vessel;
(l) (Chacham D): The water may be in a vessel, it need not be a kosher miqveh; a bathtub would be fine.
 
(m) Question: According to Chacham D, we understand why R. Yehudah said "40 Se'ah in any case," to permit water in a vessel; but according to Chacham C, what does "in any case" include?
 
(n) Answer: It includes Mayim She'uvim (water that was drawn in a vessel), which is acceptable as long as it is deposited in the ground and doesn't remain in a vessel when used for immersion.

(o) Rav Papa, Rav Huna son of Rav Yehoshua and Rava bar Shmuel ate together; Rav Papa asked to lead Birkat haMazon, because nine Kabim were poured on him.
 
(p) Rava bar Shmuel: But a Barayta taught that nine Kabim permit one to learn, but not to teach or bless for others until immersing in 40 Se'ah!
 
(q) Rava bar Shmuel: Rather, I should lead Birkat haMazon, because I immersed in 40 Se'ah.
 
(r) Rav Huna: I should lead, for I had no need to immerse.
 
(s) Rav Chama would immerse on Erev Pesach to say berakhot on behalf of others (Rashi; alternatively, perhaps he would recite the Hagadah on behalf of others).
 
(t) The Halachah does not follow him (nine Kabim suffice).