Continuity mistake: While Tam is talking to Deanna and sits down, he says "You understood... at least a little, how I felt." While saying this, he places his left hand on his right leg. While still saying that same line, it cuts to an angle from beside Deanna and his left hand is suddenly between his legs.
Continuity mistake: To view their orders and mission, Data puts a drive into the Enterprise's computer while standing with Riker and Geordi. Riker is seen standing but leaning casually away from Data on Data's right, and Geordi is standing off to Data's left. It then cuts show the computer screen, and the three men are reflected in it. The reflection shows that Riker is suddenly almost leaning over Data's shoulder, and Geordi has moved to standing behind Data's left shoulder.
Continuity mistake: In the beginning of the episode, right after Data informs Picard that the USS Hood is on an intercept course, closing at high warp, Picard is shown in the back ground looking down at his arm rest. He looks up and turns his head to his right making it center with his body. It then cuts to a close up of Picard and he is looking to his left, and turns his head again to say "That's odd."
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.