Previously on ER: Elizabeth discovered that her mom and Mark's dad were doing it; Carter was all Whose Life Is It, Anyway? refusing help as he recuperated from getting stabbed in the damn back; Finch and Benton went on a date; Mark discovered that Holling had been hiding his lung cancer from him.
David "Holling" Greene and Mark "E. Post" Greene are tinkering with a very aged slide projector. Holling asks if Mark got a bulb, and Mark tells Holling he's lucky Mark found it, because the particular model in question has long since been discontinued. Holling nostalgically remarks that they probably haven't looked at the slides in twenty-five years, and that Mark's mother used to make Holling take his camera everywhere. Mark ignores him and says that he's made Holling an appointment with an oncologist. Holling's face falls; he abruptly gets up and reminds Mark, "I told you I didn't want that." Mark implores Holling at least to talk to the oncologist, and now it's Holling's turn to ignore him and ask for the bulb. Mark takes it out of the box (and not without Holling's chiding him not to get his fingerprints on it), and Holling says, "In San Diego, they said the cancer was incurable." Mark points out that that doesn't mean it's untreatable. They futz with the projector some more; Holling tells Mark to plug it in and, holding a slide up to the sunlight, says it's from their trip to the Grand Canyon. Mark plugs in the slide projector, and the bulb pops. Heh. Holling glares balefully at his bald, ineffectual son, and says, "You must have bought the wrong bulb."
Isabel "Mama" Corday is packing up her suitcase, ably assisted by Elizabeth "Mewl, Britannia" Corday. She starts to empty a dresser drawer, first pulling out a lone man's sock. (That is, a lone sock, not the sock of a lone man.) Tartly, she asks what she should do with it, and MC giggles girlishly and asks her to return it to Holling. Elizabeth grumbles, "Do you suppose he wore only one sock home?" MC non-sequiturs, "He's a sweet man. Much like his son." Hey, I didn't know Mark had a brother! Elizabeth asks, "Does that mean you approve?" MC says, "I more than approve," and that Elizabeth glows when Mark's around, adding, "You two belong together." Elizabeth beams, and ruefully asks, "Since when have you been an expert on relationships?" MC says she's enjoyed being single, and has no regrets: "What about you, Elizabeth? What will make you happy?" Serenely, Elizabeth asks, "Do you really want to discuss this as you're about to leave?" MC sort of shrugs, and Elizabeth suggests that, since MC's plane leaves so late, MC drop by the hospital for coffee. MC agrees. Elizabeth hauls a pair of plaid boxers out of the dresser and brats, "Mother?" MC laughs and asks Elizabeth to return those as well. If Elizabeth finds a cock ring in there, I am so out of here.