diff --git a/exercises/091_async7.zig b/exercises/091_async7.zig
index 1b83795..629d276 100644
--- a/exercises/091_async7.zig
+++ b/exercises/091_async7.zig
@@ -52,6 +52,12 @@ fn increment(io: std.Io, state: *SharedState, times: u32) void {
         state.mutex.??? catch return;
         defer state.mutex.unlock(); // <-- what's missing here?
 
+        // Sleep to give the other tasks a chance to run in the meantime.
+        // We do this here only to make nondeterminism more visible.
+        io.sleep(std.Io.Duration.fromMilliseconds(1), .awake) catch {};
+
+        // What happens if you neglect to lock the mutex?
+
         state.counter += 1;
     }
 }
diff --git a/patches/patches/091_async7.patch b/patches/patches/091_async7.patch
index b4bab9b..3b6b789 100644
--- a/patches/patches/091_async7.patch
+++ b/patches/patches/091_async7.patch
@@ -1,5 +1,5 @@
---- exercises/091_async7.zig	2026-04-02 10:50:08.142508099 +0200
-+++ answers/091_async7.zig	2026-04-02 10:49:59.629341593 +0200
+--- exercises/091_async7.zig	2026-04-18 23:30:40.963951835 +0200
++++ answers/091_async7.zig	2026-04-18 23:33:47.313340585 +0200
 @@ -49,8 +49,8 @@
      for (0..times) |_| {
          // Acquire the lock before modifying shared state.
@@ -9,5 +9,5 @@
 +        state.mutex.lock(io) catch return;
 +        defer state.mutex.unlock(io);
  
-         state.counter += 1;
-     }
+         // Sleep to give the other tasks a chance to run in the meantime.
+         // We do this here only to make nondeterminism more visible.