Continuity mistake: When Carter picks up his crutches from the floor of the lounge, his hand is near the crossbars. When he hoists himself up, the shot shows his hand near the top of the crutches.
Revealing mistake: Near the beginning of the show, Mark's father puts a bulb into an old slide projector. Then there is a small explosion with smoke and flames - watched carefully, we can see are actually coming from the other side of the projector - the flames can be seen shooting parallel and close to the floor, which wouldn't have happened if the explosion actually came from the projector.
Continuity mistake: When Carol and Carter are discussing the overdose patient with nurse Dory, Carter's crutches change position and then return to their original position, even though no one adjusted them.
Continuity mistake: When Carter leans his crutches against the lockers in the lounge, we can see two pictures taped to his locker. However, after he picks his stuff up off the floor, the pictures have mysteriously disappeared.
Continuity mistake: When Carter goes into the lounge, he leans his crutches against the lockers and then moves his bag off his shoulder. One crutch falls to the floor, then the bag, then the other crutch. When the shot changes to show these items on the floor, the bag is lying neatly on top of the crutches - an impossibility due to the way they all fell.
Answer: It was in "Chaos Theory", the first episode of season 9 (time code 00:13:55).
Super Grover ★