 House heads off to Stacy's to confirm that she has not told Mark that House is with her, and the two of them wait for the rat to come out to take the antibiotics in the bait.He reveals the rat's urine shows signs that someone in the house is smoking – Stacy has been doing it secretly and started two weeks after House's surgery.They share yet another moment over her misery over his pain and how she caused his pain, and they start to consider a kiss when the rat sets off the trap.