Rabbi Silber's Daf Yomi shiur on Chullin 32 works through the halachos of shehiya - the pause during shechita that can invalidate it - and the related question of whether an animal that dies from a botched shechita is a neveilah or a treifah. He draws out that Rabbi Akiva's willingness to retract his own position and agree with Rabbi Yishmael teaches that changing your mind, even about deeply held views, is a strength rather than a weakness. He then takes the principle that "the Mishnah never moves from its place" as a picture of Torah itself: in a world where everything keeps shifting, Torah is the anchor that stays fixed, generation after generation.
Being willing to change your mind, even about long-held views, is a sign of strength, not weakness - if Rabbi Akiva could retract his position, so can we.
Torah is like an anchor: while society's values keep shifting, the same Mishnah studied by our grandparents anchors us in the same place today.
There is a time to press a hard question and a time to hold back, as reflected in Rav's hesitation to press his uncle Rav Chiya for details.
An animal invalidated during the shechita process itself is a neveilah, which conveys tumah, while one invalidated by an unrelated cause found after a valid shechita is a treifah, which does not.
The Shulchan Aruch measures the pause (shehiya) that invalidates a shechita by the time needed to lift, lower, and slaughter that type of animal, while the Rama rules that Ashkenazim treat any pause at all as invalidating.
