You could try the football stadium/bleachers at a public school. Indiana schools are closed at the moment, so there will probably not be many people around. Stadiums usually have several stories of continuous steps, and running up and down those steps is a common workout for sports teams.
Of course whether you can actually get access to the stadium steps will depend on the school, some stadiums may be surrounded by a fence with a locked gate. My high school stadium was usually open to the public except during football games, and members of the public often used the track.
You could just go there and see if it seems reasonable to get access. If there are no signs saying not to, and you can get to the bleachers without going through any locked gates, then it's probably alright. You could check out the various schools on Google street view to see which ones have stadiums and whether they seem accessible. If you want to ask permission, there's contact information on this page for the Indianapolis school district's COVID-19 response.
Another suggestion: Sledding hills in public parks. This website has a list of "best snow sledding hills in Indianapolis." It also has all the hills on a map so you can easily see which is closest to you. A sledding hill will probably be pretty muddy at this time of year, but also should be pretty much deserted.
Also according to this discussion about hilly places to run in Indianapolis, there is a hill you can run in Crown Hill Cemetery. They recommended entering at 34th and Boulevard Place, but I can't tell from the map exactly where the hill is, or how long it is.
