Sloane pulls Nadia's hand from Lazlo Drake's grasp but after a cut Drake is holding it again.
When Sloane and Sydney are standing in front of the TV looking at their own image from a camera nearby, Sydney raises the remote control to switch to another channel. However the Sydney in the picture does not move her hand.
It is inconceivable that it has taken this long to uncover the bug in Nadia's necklace. As trained agents, both Sydney and Nadia would regularly sweep their apartment for listening devices and it would have been discovered. Likewise, one would expect the APO office would also do security sweeps regularly.
Yanking the glass shard out of Sloane's chest the way Nadia did is an extraordinarily bad idea. The proper field procedure is to apply pressure to the wound around the glass shard. Nadia, as a field-trained agent, would have known this.