tldnr is that Rust guides the programmer only halfway to the solid engineering solution, the programmer is on their own to make the arena solution safe.

its a pedantic nitpick, as is his way. also keep in mind that of late Blows focus has been single player video games made by very small very talented teams. A domain where the benefits of Rust are very small, possibly even a net loss compared to the fast compiling language they use now.