Lifetime and scope clarification in Closure types reference.

As I understood so far, lifetime is affecting the borrowing rules enforcement, scope on the other hand, has to do with memory deallocation.
Most of the time, these two concepts are not overlapped.
The only case I'm aware they do, is that of the temporary variables in `let` statements.

src/types/closure.md

@@ -95,12 +95,12 @@ reference, as in the following example:
 ```rust
 let mut b = false;
 let x = &mut b;
-{
-    let mut c = || { *x = true; };
-    // The following line is an error:
-    // let y = &x;
-    c();
-}
+
+let mut c = || { *x = true; };
+// The following line is an error:
+// let y = &x;
+c();
+
 let z = &x;
 ```
 
@@ -110,8 +110,9 @@ because a `& &mut` reference might not be unique, so it cannot safely be used to
 modify a value. So a unique immutable borrow is used: it borrows `x` immutably,
 but like a mutable borrow, it must be unique. In the above example, uncommenting
 the declaration of `y` will produce an error because it would violate the
-uniqueness of the closure's borrow of `x`; the declaration of z is valid because
-the closure's lifetime has expired at the end of the block, releasing the borrow.
+uniqueness of the closure's borrow of `x`; the declaration of `z` is valid because
+the closure's lifetime has expired, i.e. there are no `c` calls after `z`, 
+releasing the borrow.
 
 ## Call traits and coercions