S01E07: 'The Self-Desctruct Button'

Derek and Meredith try (unsuccessfully) to be discreet as they spend the night together at Meredith's house but their haggard appearance speaks volumes to everyone - including Bailey, who warns Meredith to end the relationship.

Meanwhile, George suspects an anesthesiologist of drinking on the job but is reluctant to speak up about it.

Alex treats a former schoolmate who finds honour in self-mutilation.

Izzie's boyfriend takes extreme measures in order for them to spend more time together.

And Cristina seems to be battling a case of the flu.