Oswald didn't just give up his revenge for Ed, he gave up his assurance. After everyone who has betrayed him in this episode and all season, he's got to be in the mindset of "if you want something done right, you have to do it yourself".
Sofia posed a very real, very terrifying threat not only to Oswald, but to Martin. Giving up his revenge is one thing, but the fact that he chose not being there to ensure her death himself in favour of saving Ed's life is an incredibly enormous sacrifice, and one I hope neither Ed nor the writers take lightly.
















