House finds the problem in the surgery footage: abdominal epilepsy
Surgery finds nothing and the team calls Mark healthy; House replays the video, enhances it, and spots the twitch nobody saw.

Every House moment featuring Robert Chase, in story order. Played by Jesse Spencer.
127 moments · 3h 22m · by Favseen
Moments 121–127 of 127
Surgery finds nothing and the team calls Mark healthy; House replays the video, enhances it, and spots the twitch nobody saw.
Searching the Warners' house, they find a teasing note from Stacy and a stash of amphetamines with a story behind them.
Foreman rules out Guillain-Barré; House pushes a long shot where the body fights nothing, and the team agrees the treatment is low risk.
Mark accuses Stacy of leaving the way she left House; mid-crisis the room calls a code, and House reads the vitals as panic.
House replays Mark's honest-looking Paris answer, then lays out a disease that leaves no fingerprints, down to the yoga.
Mark refuses House's trigger shot; Foreman, Cameron and Chase block him, House mocks the stand, and he still gets his way.
Mark convulses while the team fights over Ativan and a sample; the urine stays yellow until House adds light.