At this point there is no real "nest", it's really just a pile of twigs.
So unless they are that far behind in nest building and she is desperate to get the eggs out of her womb, its unlikely that eggs have been laid yet. I decided at that point to stick around for the day and see what would develop.
After a few minutes she got up and began assembling some sticks around the nest, then headed towards some Sweet Gum trees to acquire more twigs. I decided to take a few pics to make sure there were no eggs on the fire escape, and thankfully there weren't. I watched her go back and forth gathering twigs for at least half an hour before she decided to take a break.
As I watched her perched on the fire escape, her mate appeared from above the building and landed right next to her.
(Female on the left)
After a few seconds together, they decided to copulate.
After mating, they separated and perched near each other for a few moments before taking off to find a meal. They did not return to the nest for the rest of the day as far as I could tell, so I'll have to wait till tomorrow to see if they return and continue work on this nest.