Well, there's two interpretations of "all bets are off". One is the runtime one, which is if you have a bug in unsafe code, then it is possible that all the other code in your program is safe but you're still totally out of luck because it can invalidate every guarantee. However, from an auditing perspective, the only code you need to look at for memory safety issues is that particular snippet, so you're in a much better position from that perspective.