At around 2 minutes into the season 5 episode 'Gliding All Over' of Breaking Bad, Walt stares at a fly on the desk lamp at the 'office' supposedly a little while after...
Todd walks in and says "Should we deal with this other thing now?" To which Walt replied: "Yeah". He puts on his glasses and as he leaves the frame, the shot focuses on the poster depicting various flies on the wall behind him.
Is there any significance or symbolism behind this shot?