It's going to be incredibly awkward and Booker's going to have to think long and hard about the decisions that brought him to this place in his life.

I'm still working out what canon point I want Booker to be in from but I'm leaning towards pretty late in Bioshock Infinite (either the part with Too Many Lighthouses or shortly after witnessing the seed of the prophet sitting the throne and drowning in flame the mountains of man, as predicted), and he's been in Aria for a good long while so he's. Going to have an emotion, finally seeing Elizabeth again after all this time. Even if she is a monster now because hey it runs in the family I guess.