Since it's frowned upon
(ahem, illegal) to go inside the buildings without permission, there are not that many photos/videos from inside the walls, which is why I was surprised to see these appear on Youtube just last week (12/23/20).
A user by the name of @mR. cHoW posted the video and refers to himself as Mike in it. The images above are stills from the video he captured. Mr. Chow does goes for a drive and gets gas for the first 17 minutes and change so
skip ahead to the 18:00 mark to see inside. At the 25:00 mark, he encounters a flood in the stairwell.