An exterior effects shot of Serenity, as it heads toward the net, shows the port-side shuttle still in place despite the fact that Saffron has already departed and stolen the shuttle.
Jayne says that his gun ("Vera") needs oxygen around it to fire. The gun is shown with standard projectile rounds, which produce all the oxygen they need. According to the DVD commentary, the producers were not sure if "Vera" would need oxygen to fire and asked a gun expert, who gave them the wrong information.