Breaking Bad S3E10 (Patreon)

Its 12:30 am and I'm sitting here thinking about this episode. 

https://1drv.ms/u/s!ApS4U77vEa2DtQlCs-bWxxHd-zBO

The fly!!!!  Ok, so maybe I'm reaching here but after re-watching a few key scenes it got me thinking about symbolism. The way Walt was trapped first with this annoying fly, Jessie coming in and not really thinking that the "contamination" was that serious, Walt being obsessive over it and telling Jessie that this contamination would destroy everything, and then how it focused on their relationship and Jane specifically. So if we are going with the idea of the contamination being Walter and Jessie's relationship because of what happened to Jane, then we can say that the fly is a representation of Walter's guilt for killing Jane and he fears that what happened would end up destroying his relationship with Jessie. So he goes back to that night, the perfect moment before he did that to Jane and he didn't have that guilt. Then it's Jessie who tries to catch the fly, violently swatting at it while Walt tries to tell Jessie that he was sorry. Jessie tells him that its not his fault and finally kills the fly, relieving Walt of that guilt.  But the relief is only momentary because the fly, the guilt, is still there when he goes home. Still think it can also be foreshadowing some future event too. That there will be an actual contamination one day and Jessie will have to deal with it because Walt wont be able to. Idk, I think this episode could have many interpretations. What do you guys think?

Edit: Also is the possum story supposed to tell us Walter's cancer might return? Because Walter said that he went to the doctor and he was still in remission but Jessie also said that his aunt continued to feel the presence of the possum even though it wasn't there anymore and then she discovered that her cancer had spread. Idk, this episode messed me up LOL