Episode 81 of "Scrubs"
s04e13 My Ocardial Infraction

J.D. and Elliot are finally again getting along as friends and work partners, but the balance is upset when Elliot starts showing J.D. up as the calmer, more competent doctor, thus allowing her to teach him a few things. Where Elliot's cool is almost lost is when she realizes The Janitor may have had more in mind for their cafeteria "coffee date" when he shows up in suit and tie. His explanation for his attire leads to an a cappella sing-off between his "group" and Ted's band. Meanwhile, Turk starts taking his diabetes more seriously when he realizes the dire consequences of the disease, until Carla reminds him that his sense of humor is what helps them both cope.