Continuity mistake: In the scene right before the shuttle's crew finds the Romulan ship and the Enterprise, Geordi calls the shuttle craft's cockpit to explain the temporal disturbances. Captain Picard, Troi and Data walk into the shuttle's cockpit room and Troi puts her right arm on Geordi's chair. As Geordi, Data and Captain Picard are talking you can see Troi's wrist hanging off the chair, but when the camera cuts directly in front of Geordi her whole wrist is on the chair. The camera then cuts back and you can see that Troi's wrist is still hanging off the chair.
Continuity mistake: In the scene where Captain Picard reaches for the aged fruit, he screams while holding his right wrist with his left hand. As Troi, Geordi, and Data rush in you can see Captain Picard holding his wrist up in the air. The camera then cuts directly in front of Captain Picard and you can see Troi scanning his wrist but he isn't holding his wrist anymore. The camera then cuts directly in front of Troi and Geordi and you can see that Captain Picard is still holding his wrist. The camera then again cuts back to Captain Picard and he isn't holding his wrist anymore.
Continuity mistake: Picard states that the energy beam appears to come from the deflector array, in later shots it is coming from the rear of the star drive section.
Answer: Yes. The doors to the holodecks can be locked when in use by anyone aboard the Enterprise so they couldn't be disturbed. However, high ranking officers like Captain Picard could override the doors as it's seen that overrides are in use even for the crews quarters. Even Barclay, when he's indulging in one of his fantasies could have the doors to the holodeck unlocked by an override code.