Yes, these kinds of transfer numbers are easily possible (even though other posters have said you don’t actually have 1,000 getting on or off at one stop). As an example, consider the subway of Toronto, Canada on its busiest line, Line 1. A subway train is 138m (450 ft) long with 6 cars (though there is no internal barrier between cars) and a capacity of about 1,500 people. Each car has 4 door sets per side, and these door sets are about 1.5m (5 ft) wide. People can easily fit through them in pairs, so moving 4 or more people per door set when in a rush is very doable. With 24 door sets (only one side opens at a station), that’s 96 people entering or exiting per second, so 10 or 11 seconds for 1,000 people. If you think 4 per second per door is too optimistic, then it’s 1,000 people in 20 seconds.

At least where I’m from (Canada), bread comes with a clip holding the bag shut, not a twist tie. “Re-using the clip” means the clip the came with the bag. You can see that it’s a different shape in the picture. This would be the equivalent of re-using the twist tie, if that’s how the bread is packaged where you live.