u/80sSlasherLibrarian

I now know the budget reason and have since figured out it was Walt's paranoia and guilt etc. However on my first viewing, especially with it starting with the net math not mathing, I thought it was Walt knowing deep down Jesse was stealing meth from the lab and the fly/contaminent was Jesse. That Walt was seeing that Jesse was a contaminent or even Walt feeling he had contaminated Jesse. Mostly I thought it was Walt realizing that Jesse was contaminating what they had by stealing a la the fly contaminating the lab. I see the actual reason clearer now but thought I would share.