diff --git a/Chapter04/worker.cpp b/Chapter04/worker.cpp
index e8db894..4554c9f 100644
--- a/Chapter04/worker.cpp
+++ b/Chapter04/worker.cpp
@@ -31,6 +31,7 @@ void Worker::getCondition(condition_variable* &cv) {
 // --- RUN ---
 // Runs the worker instance.
 void Worker::run() {
+	unique_lock<mutex> ulock(mtx);
 	while (running) {
 		if (ready) {
 			// Execute the request.
diff --git a/Chapter04/worker.h b/Chapter04/worker.h
index 109ce1d..15af25f 100644
--- a/Chapter04/worker.h
+++ b/Chapter04/worker.h
@@ -26,13 +26,13 @@ using namespace std;
 class Worker {
 	condition_variable cv;
 	mutex mtx;
-	unique_lock<mutex> ulock;
+	//unique_lock<mutex> ulock;
 	AbstractRequest* request;
 	bool running;
 	bool ready;
 	
 public:
-	Worker() { running = true; ready = false; ulock = unique_lock<mutex>(mtx); }
+	Worker() { running = true; ready = false; }
 	void run();
 	void stop() { running = false; }
 	void setRequest(AbstractRequest* request) { this->request = request; ready = true; }