Fly

Walt is suffering from insomnia, worried about the choices he has made and the direction his life has taken. Unaware that Jesse has been skimming a bit of their product, he also worried that the numbers in his formulas don't add up and that they always seem to somewhere between 4 and 8 ounces short of what the batch should have produced. The meticulous Walt is also concerned - to the point of paranoia - when he discovers a housefly in the lab. Worried about contamination, he goes to extreme lengths to kill it. Jesse comes to his rescue in an interesting way. Near delirium from sleeplessness and the sleeping pills Jesse put in his coffee, Walt repeatedly refers to Jane and the night she died, but stops short of telling Jesse that he witnessed her death.