They were actually doing work on the exterior of the base building that will become part of the podium of the tower. They were removing the historic Art Deco entrance detailing to work on the structure behind it and put it back into place once done.
They are making a lot more progress picking away at this. The short side section is being removed to make way for the access ramps into the parking garage. Eventually the back of the building will be hollowed out to make way for the actual tower, with most of it remaining as the podium. The art deco detailing was carefully removed and stored while they worked on the rotting wood and brick behind it. It will be put back later.
They are now demolishing the whole building. According to one of the workers on site, they realized it was too expensive to use the old building as the base so they are going to build a new facade to mimic the old building, and add the stonework they saved.