House wakes from his first real sleep to find Amber Volakis still present — the insomnia explanation is gone. While running a case involving a professional ballerina whose lungs fail mid-rehearsal, he conceals the hallucination from his team and lies to Wilson about who he is seeing. A premature antibiotic call triggers toxic epidermal necrolysis, and his attempt to self-diagnose MS collapses when the lumbar puncture rules it out and reveals dangerously elevated Vicodin levels. He injects himself with insulin, survives, and correctly identifies a gonorrhea abscess sealed from the bloodstream — but recognizes afterward that his reasoning was compromised even though the answer was right.

This episode is the functional climax of House's Season 5 deterioration. It clarifies exactly what the hallucination has been doing — not tormenting him but  ...