So, House goes to Cuddy. He tells her that the sleepless patient she gave him is now in liver failure, and will be getting a new liver from her girlfriend. Cuddy is appalled to hear that they are doing a transplant as a stopgap measure, but she will still allow House to go on his merry way, as long as she isn't involved. But now she is, because House and his team can't be Max's doctors, since Max and Hannah, House says, have "opposing interests." Cuddy is shocked that House is coming to her with an ethical dilemma. I would be too if I didn't think he was doing this to ensure that Cameron wouldn't get to Cuddy first and foil his plans. House says that the ethical dilemma is relevant to the case, but not medically so. So Max doesn't need to know it, and neither does Cuddy, now that she's Max's doctor. Cuddy goes to look up House's secret on the hospital computer, but he stops her, asking whether satisfying her own curiosity is worth Hannah's death. As long as Cuddy stays in the dark, she isn't doing anything ethically wrong by clearing Max for transplant surgery. Except that Cuddy's not exactly in the dark, is she? I mean, there's at least a small nightlight on there.
Cuddy runs tests on Max, and tells her that she's making a huge decision and should know that she could die doing this, and be certain that it's worth it. Max says that all she wants is to grow old with Hannah. They can lie in bed and compare their matching liver surgery scars. In Max's mind, things will work out perfectly.