Mitzvah Manslaughter Excluded? PT III

Ravina's קושיא on Rava is answered!
Recall that Ravina asked: If you are correct, Rava
--that if it is not a mitzvah to re-cut wood if you have found pre-cut wood for a Succah or the altar,
--then even if you do not find pre-cut wood, cutting the wood yourself would not be an inherent mitzvah,

then it should follow that ........
-- if a child is learning there is no mitzvah to administer physical force to him
-- therefore, even when a child is not learning/behaving well, it is not a mitzvah to administer physical force

However, we see from our mishna that the administering of physical force in the case of a father, rebbe etc - is considered a mitzvah, and thereby exempts the rebbe, father, from Galut!

Rava's answer:
Your equation is incorrect, because it presumes that there is no mitzvah to adminster force when the child is "in line".  Quoting a pasuk in משלי, Rava establishes that there is an ongoing mitzvah for a parent/rebbe to be "on guard" and to provide pre-emptive physical force if need be to child and student.  We can therefore say that the mitzvah to discipline a child is an inherent mitzvah, unlike the woodchopping case.

Rava then says לאו מילתא היא דאמרי.  Although Rava seems to be retracting his previous proof given to the talmid, Rashi explains that Rava merely means that he has an "even better proof" from the pasuk itself.  It hinges on the expression ואשר יבא את רעהו ביער - where the word אשר implies, for Rava - a voluntary activity.  He entered the forest voluntarily, and not out of a mitzvah obligation.  That's how we know that the חטבת עצים is a רשות - and only in that kind of case is there Galut, to exclude a case of mitzvah...

The latest stage in the Gemara is the problem raised with that from a pasuk dealing with entering the Bet Hamikdash in a state of טומאה.  Before tonight's shiur, if possible - please review the latest step in the Gemara so that we can begin the shiur with it.
See you tonight for our second last shiur of the season!