Continuity mistake: On the old subway platform when Q is about to introduce Bond to his "new transportation," they both look on as Q clicks a control to bring forth the carriage that has the still invisible Vanquish on it. The carriage almost passes them already when the shot cuts to another angle, and this time the carriage is still approaching on the railtrack from a bit farther away. Also, Q's right arm is now up holding the remote control, when in the previous shot just a second ago it was straight down by his side. (01:05:41)
Continuity mistake: When Bond uses his sound-ring to break the glass floor, we see the floor crack twice. (01:26:35)
Other mistake: Right after Bond and Jinx have descended through the clouds in their Switchblades, we cut to an airbase in North Korea. The caption (English Blu-ray) misspells Pyongyang as "Pyongang." (01:47:48)
Answer: By this stage, it's become a habit.
J I Cohen