So, of course it wasn't a simple thing. I ended up cutting down and finding lots of rebar. So, there was a lot of sledge hammer work. It took all day.
The interior doors were also a huge challenge, as it turns out the floors were different heights, and the rebar made it hard to run a single line.
The concrete chainsaw made a pretty big mess inside as well, but I did manage to get the doorways clear. My arms hurt just looking at these photos.