Taub and Chase run into Sir William's room, where Hadley is standing around a bunch of beeping machines. She says his heart rate is slowing, but doesn't seem to want to do anything about it. Instead, she notices that Taub and Chase aren't wearing their anti-MRSA suits and asks what's up, because that's the most important thing right now. Taub quickly tells her it isn't MRSA as Chase runs up with a syringe of epinephrine. Taub advises against that, saying it could "blow [Sir William's] heart out." Chase does it anyway. Oh, and then Sir William's heart stops. "I told you!" Taub says, because now is definitely the time to lord your personal victories over your co-worker. Especially since one second later, Sir William's heart rate is back and normal. "And I told you," Chase says.
So now that Sir William has a heart problem, poison ivy is no longer a credible diagnosis, nor is an epinephrine allergy. Chase suggests an infection caused by a usually harmless bacteria taking advantage of Sir William's weakened immune system. But House doesn't like any of their choices for what could have caused Sir William to have a weakened immune system, so he goes back to his environmental thing. Hadley insists that they tested all of the food stands at the fair and they were (shockingly) clean. "Maybe he got the poison somewhere else. Or maybe you just missed it," House says. He orders them to treat Sir William for trichinosis, then do a muscle biopsy to test for it.
House finds Wilson in the main lobby, and Wilson reluctantly invites him out to dinner with him and Sam, saying Sam wants to get to know House better and thinks Wilson was trying to hide his roommate from her. Which he was. And was wise to. But he doesn't want her to know that, so he's forced to take House out to dinner. Very stupid, Wilson. I would have just told Sam I was hiding him from her. Once House ascertains that Wilson is "asking [him] to condone a relationship based on lies and mistrust," he only wants to know "when and where?" Wilson says it's tonight, which is really short notice, especially since House doesn't know what to wear since "all of [his] cereal boxes are at the cleaners." Wilson tries to level with House, saying that while he appreciates him trying to look out for him, he doesn't need or want his help. "Come to dinner and be your usual selfish self," Wilson asks. He can't possibly think that's the best way to phrase that, right?