Mark's watch reveals that he enters Lumon on the 4th day of the month. Later that same day, when Mark leaves Lumon, the date on his watch now shows it's the 5th, and the crown on his watch is unscrewed.
When they are in the interview room, Marks points with the right hand open to Helly to please take a sit, in the next take he has is the left hand open pointing to it.
When Helly is locked in the conference room, she attempts to turn the door lever several times, but it doesn't move. Later, when the door is seen from the other side, the lever is moving up and down (the door being secured only by a deadbolt).
The instructions state that the candidate has to ask three times to leave in order to be allowed to exit the room. Between Helly waking up on the table and the moment Mark instructing her to ask one more time to leave, she had already asked four times to be allowed to leave, in the forms of "Let me out" or "Let me out of here".
Rather than an error in the screenplay or editing, this may be a deliberate reflection of Mark's harried mindset and his failure to thoroughly understand the instructions.
Rather than an error in the screenplay or editing, this may be a deliberate reflection of Mark's harried mindset and his failure to thoroughly understand the instructions.