I can't say for this specific building but sadly for many office buildings it would be cheaper to knock them down and build an apartment building than convert them. I know it is dumb but true.
I'm riding the high of my hometown converting an ol office building that is a historical part of our skyline into a shopping center on the bottom floors and apartments above it.
I get that this isn't always feasible but I'm feeling optimistic
Or a giant indoor maze that takes multiple days to finish. Elevator to the top, pack in a backpack or supplies. Complete challenges for coins that can be used at 'trading posts' or too unlock levels. Have trick stairwells and stuff, levels that dead end where you have to go back up and find amother way down.