"WHAT ARE YOU MISSING?" House shouts again. The answer comes from the back of the room: "Muscle death." The answerer is Cameron, who apparently decided to spend her lunch break ruining her boss's lecture. I mean, GOD, Cameron, he was trying to make a point there, both for himself and his students, and you freaking came in and crapped all over it! House looks annoyed, probably because Cameron gave his students the answer and because if she's in there, it means the rest of the opening credits cast will be sure to follow. He tells Cameron that this isn't her case. Smirking, Cameron says that there's "nothing wrong with a consult." Yeah, except that the definition of a consult is advice or information one solicits from another party. And no one asked for your opinion. Go away. StudentCameron latches onto her counterpart's diagnosis, of course, and House says they'll give the druggie an MRI to find out what's wrong with his leg. But it's the volleyball player, not the druggie, who slides into the MRI of DOOM, which doesn't escape the notice of StudentForeman, who's still not observant enough to get rid of that unflattering greasy long hair. House keeps going that the adenoma scan revealed nothing, so her obsessive weirdo doctor (cut to Cameron, looking uncomfortable) ordered an MRI. As for the druggie, neither the students nor his doctors came up with Cameron's muscle death diagnosis, believing it to be the trauma thing and giving the patient bedrest and antibiotics for the three days while his condition worsened. House tells the students that they are bound to make a mistake that kills a patient. If they can't handle that (ahemCAMERONahem), they should do something else with their medical degrees, like teach. StudentCameron can't believe that three whole days went by before the doctors figured out the muscle death thing. House that it wasn't the doctors who diagnosed it at all, but the patient himself.
Back in flashback land, Cameron informs the volleyball player and her parents that the MRI revealed a cancerous tumor in her leg. It will have to be surgically removed, and she'll need chemo, but her chances of survival are excellent. Her leg may have to be removed, though, depending on how big or embedded that tumor is.
Foreman tells the farmer that they found flesh-eating strep bacteria in his dog's mouth. They'll have to remove the damaged tissue from the farmer's leg, and maybe the entire leg as well.
Cuddy herself tells the druggie that the MRI did, in fact, reveal the source of his leg pain. She's really sorry that his doctors were all incompetent ninnies who didn't catch it when it started, and promises to oversee his treatment personally from here on out. The druggie asks if he'll need surgery. Cuddy says they may need to remove his leg.