Luka was untied and so was Julia. When Alexander came into the cell a day ago, he had freed Luka and Julia while saying, "I'm doing this so both of you realize that I'm not that much of a bad person."
Alexander had stayed there for several hours until the end of the day without saying anything and no one else talked. He left at exactly midnight.
Luka assumed that Alexander had no idea about Julia's unusually fast recovering Pixie powers because this way—she had whispered to Luka—will let her heal faster.
Luka hadn't talked about his child with Julia—assuming that she already knows—but when Alexander mentioned it before leaving, Julia had a look of horror on her face.
"You're pregnant?!" Julia didn't know what to say. She wasn't expecting this to happen so soon. When Alexander stole her soul once again, she thought that there would be at least a century until they had to face The Prophecy.