Not sure if there's a topic about this already, but I couldn't find any. In Star Trek Generations, the crew had five minutes to leave the stardrive section and go to the saucer section. My question is: how did they know everyone left the stardrive section and went to the saucer section? Did they use sensors, something else or nothing at all? Just wondering, that's all.
The ship was in active combat with holes being blown in the hull- I think people would be ready to make a quick exit to the Primary hull or escape pods, just waiting for the official word to book it. EDIT With about a thousand people to get to safety I think the connecting doors will close at a certain time regardless if people are still left in the stardrive section or not. Personally I think they waited to long to separate since when the warp core blew it knocked the saucer out of control into the atmosphere.
The other thing to consider - the majority of those thousand crew members were probably already on the saucer section as that's where most of the off-duty, non-Starfleet personnel lived and resided. There was probably only a fraction of the crew in the drive section that needed to be evacuated to begin with. Along with this theory, there's probably a safer, shielded zone in the saucer that everyone had to get to - which is why we saw Geordi and Dr. Crusher shuffling people out of sickbay and down the corridors in the lead-up to the crash.
I'm sure there's a protocol to be followed. Crewmembers in charge of the evacuation might be responsible for a specific group of people, and once a crewperson sees that their group is all clear, they hit the 'button' to register that their group is safe. Once all 'buttons' have been hit, the stardrive section is confirmed as cleared.
Maybe they didn't know everyone left the stardrive section. The warp core is gonna blow up, gotta evacuate, gotta detach the saucer and get away in minutes--with or without knowing everyone has left the stardrive section, even without an "ALL CLEAR". Given the critical circumstances, they'd have to cut and run even if some persons were still left in the stardrive section.
If you listen to the Braga/Moore DVD Commentary, they state that the teddy bear the little girl Geordi is carrying drops, is a sentient life-form that is killed when the star-drive section detonates.