Nobody on the bus notices Elway grabbing Hannah's arm or hears him talk about taking her in. Nobody notices Hannah stab him the knee with the syringe either.
In the flashback scene between Debra and Dexter in the hospital, the mesh lining of a wig the actress is wearing (to reflect her older hair style) can clearly be seen in the parting of the hair.
When Dexter has a flashback of himself and Debra in the hospital, it's obvious the baby they are holding is a doll in most shots.
When their initial escape at the airport goes awry, Dexter says that the detective following them will be monitoring all the flights to Rio so they'll need to find another airport to fly out from. The plot has always been that they are escaping to Argentina. Rio is in Brazil, not Argentina.
The ambulance crew refer to Debra as Lieutenant but at the time she was back to being Detective.