Stacy stares at House. He says he can't give Mark the injection. Stacy looks more angry that her orders aren't being followed than she does sad. How did Sela Ward win not one, but TWO Emmys? I'm pretty sure I enjoyed her in the few seconds of Sisters I caught on Lifetime once. What happened? Come to think of it, Stephen Collins was well-regarded for his work on Sisters too, and now look! Maybe Sisters is cursed. Someone should go check up on Swoosie Kurtz. House walks over to cabinet and puts the syringe down. The Cottages unclench. Whoops! House was just playin'! He spins around and stabs Mark in the leg -- the right one, which is the same one Stacy took away from House, probably not coincidentally. "You son of a bitch!" Mark growls. "See what I did there?" House says to no one, since everyone totally did see it. Cameron and Chase go to check on Mark, who seems fine, which indicates that the AIP diagnosis was wrong after all. Foreman tells House that he just set Mark up for all kinds of deadly things, and then Mark has an attack. "What's happening? Is that an attack?" Stacy inquires stupidly. Cameron goes to give Chase a syringe of Ativan, but House knocks it out of her hand with his cane. Sadly, he does not appear to hit any part of Cameron's body in the process. He says that there will be no Ativan until they get the urine sample. Foreman says that their patient is having a stroke, and House points to the brain waves on a monitor as proof that he isn't. Mark thrusts and screams, knocking out his catheter along with their hopes of getting a urine sample. Foreman says that Mark's heart is failing, and that they will lose him if they don't do something right now. House sticks a long needle directly into Mark's bladder, which Mark does not enjoy. But it yields a fresh urine sample, and they can finally give Mark his Ativan. Stacy wrings her hands in what is supposed to be worry.
House tests the urine himself, without using latex gloves, because who doesn't like getting piss on their hands? The Cottages observe as House puts something in the urine and swishes it around. "It's still yellow," Cameron informs him, as if he didn't know this already. House grabs another light to encourage oxidation. If only the lab wasn't so concerned about looking all high-tech and cool and had better lighting instead! With the additional light, the piss turns black, meaning it's positive for porphobilinogen and therefore, for acute intermittent porphyria. House orders them to start Mark on glucose and hematin. They leave, and House takes a minute to express more emotions with his eyes than Sela Ward can with her entire face. Goddamn that alleged plastic surgery!