There are no 'unsafe' blocks in Fil-C. I think you trying to conflate 'unsafe blocks' with the fact that there might be compiler errors which might break 'safety'? Which is equally true in any system including Rust.
Any safe system has unsafe parts. Quibbling about whether these parts are called "blocks" isn't useful. The term changes nothing.
Exactly, my point is that the compiler and runtime are the "unsafe" portions of Fil-C, and that Fil-C and (safe) Rust are equivalent in this regard.