diff --git a/src/unsafe/calling-unsafe-functions.md b/src/unsafe/calling-unsafe-functions.md
index 042e2182..6c0bc920 100644
--- a/src/unsafe/calling-unsafe-functions.md
+++ b/src/unsafe/calling-unsafe-functions.md
@@ -10,9 +10,19 @@ fn main() {
     // Safe because the indices are in the correct order, within the bounds of
     // the string slice, and lie on UTF-8 sequence boundaries.
     unsafe {
-        println!("{}", emojis.get_unchecked(0..4));
-        println!("{}", emojis.get_unchecked(4..7));
-        println!("{}", emojis.get_unchecked(7..11));
+        println!("emoji: {}", emojis.get_unchecked(0..4));
+        println!("emoji: {}", emojis.get_unchecked(4..7));
+        println!("emoji: {}", emojis.get_unchecked(7..11));
     }
+
+    println!("char count: {}", count_chars(unsafe { emojis.get_unchecked(0..7) }));
+
+    // Not upholding the UTF-8 encoding requirement breaks memory safety!
+    // println!("emoji: {}", unsafe { emojis.get_unchecked(0..3) });
+    // println!("char count: {}", count_chars(unsafe { emojis.get_unchecked(0..3) }));
+}
+
+fn count_chars(s: &str) -> usize {
+    s.chars().map(|_| 1).sum()
 }
 ```