Sys exit does not crash. It raises a SystemExit exception, which can be caught on any layer above it. Given that python uses exceptions for trivial things like loop termination this can be considered normal flow control.
Yeah, and in Rust you can catch the panic from `unwrap()` with panic::catch_unwind. You just don't, for the same reason you don't catch SystemExits. If a SystemExit is being thrown, it's because you want to crash; if you don't wan to crash, don't throw a SystemExit.
