When House returns to Apple's room, he finds two security officers have been posted at the door. I wouldn't be too afraid of them, House. PPTH's security officers have been known to allow gun-wielding madmen into the hospital to shoot unsuspecting doctors, and then let them get away. But House has to turn away, discouraged, as music starts to play.
He sulks in an empty office. As the camera pans to reveal that it's Wilson's empty office, he makes a phone call.
Someone screws around with Apple's IV bag. She starts to crash and the mystery man walks away and nurses run in to save her. We don't see his face and the nurses don't wonder why he's walking away from a code, and in slow motion. We do see his argyle socks, which is all we need to identify him. Kind of like Nanny from Muppet Babies!
Skull drilling happens. Someone carefully removes the top of Apple's skull while Chase observes. Foreman the neurologist is nowhere to be seen, but House is observing from the OR balcony. He yells to Chase to check Apple's IV, since it looks like someone switched her chemo with saline. It takes Chase a minute to figure out what he's getting at. "You switched her meds?!" Chase asks. "How could I? I wasn't allowed access," House says. Chase gives the order to close Apple's head back up since there's no reason for the surgery anymore. House shrugs that they've already done the dangerous stuff, so they might as well see it through. The brain surgeon seems to agree: "we're ready with the neural net," he says. Aw, he just wants to use his neural net. Chase is pissed, but trusts House enough to continue the surgery.
As they do that, House gets a visitor: the PI. He's thrilled to see an actual brain down there until he realizes that the surgery is being performed on Apple. House apparently told him that swapping someone's meds wouldn't hurt her at all. "I'm a better liar than you are," House says. You think that when Apple crashed PI didn't get a clue that this wasn't harmless? House explains that the neural net will show them if the neurons aren't firing though a certain part of Apple's possibly-cancer-stem-cell-ridden brain, and then the surgeons will be able to cut that part out and she'll be all better except for the inevitable brain damage. "Cool," says PI, although he doesn't really think it's cool. He's just telling House what he figures he wants him to say, since House is basically paying him to listen. With that, the neural net finds the not-brain-brain and PI charges House five thousand dollars. House doesn't seem to mind that too much.