When the Enterprise is accelerating out of control, the warp core should be thrumming at a very high speed. However, in the entire scene in engineering, it is never seen to pulse faster than it does at idle.
In the meeting with LaForge's senior officers, Wesley suggests to Lt. Barclay that he should check the flow capacitor on his malfunctioning anti-gravity device. In the next scene, Barclay tells Troi that he already knew about the "flux capacitor". This is hardly an error because 'flux' means 'flow'.
(The flux capacitor is the famous fictional device from Back to the Future (1985) that makes time travel possible.)
When Picard calls La Forge on the holodeck regarding the injector problem, he forgets to activate his com-badge first. However, as has been seen in previous episodes, on the bridge, activating the com-badge is unnecessary. All the bridge requires is voice activation.
Just after Picard tells La Forge to make Barclay his "project", he turns his display screen towards him to study it, but the screen is blank.
In many of the physical-combat scenes, obvious stunt doubles are used in place of the actors for the wide-angle/far-away shots. A notable example in this episode is where (in the far-away shots) an obvious fight/stunt double can be seen sword-fighting in place of Dwight Schultz (Lt. Barclay) on the holodeck.
When Troi and Barclay are leaving the holodeck, the floor looks like black carpet with yellow tape stuck to it it simulate the hologram.
Both times the holodeck is deactivated (via bluescreen effect), the background of the holodeck is of a much different size and shape than the holodeck set the actors are then seen standing on. The bluescreen background is much larger with all corners squared off, while the actual set is smaller with rounded corners. The coloring is also different, with the bluescreened version having bright yellow grid lines while the actual set has darker golden lines.
When the holograms of Picard, Data, and La Forge draw their swords to confront the real Troi, Riker, and La Forge, the sound of a sword sliding out of its scabbard is heard. The holographic Musketeers wear no scabbards. The actors are simply holding the swords to their sides.
The Captain's error in referring to Lt. Barclay as Broccoli is a malapropism, not a metathesis as Data described.
At the briefing in engineering, Wesley tells Barclay that there could be an issue with a flow capacitor. Later, when Barclay is talking to Troi and upset that Wesley told him something he knew, he called it the Flux Capacitor.
After Captain Picard accidentally calls Barclay Broccoli, Data mispronounces the term "metathesis." He says "mettuh-THEE-sis" when it should be "muh-TATH-uh-sis."