It wasn’t an “inescapable prison,” it was a county jail in a small Indiana town.

That’s not a pitbull, it’s a Cane corso or another type of mastiff. That people so frequently misidentify various breeds as “pit bulls” is one of the factors that makes the statistics you cite unreliable. Even “pit bull” isn’t a specific breed designation. Any breed or mix with a boxy head and deep chest is likely to be mistaken for a pit bull.